All language subtitles for [English (auto-generated)] JavaScript Tutorial for Beginners - Full Course in 12 Hours (2022) [DownSub.com]

welcome to the ultimate javascript

course where you're gonna master

javascript in under 12 hours by building

projects you're gonna start off with the

basic fundamentals of javascript and

then you're gonna move on to building

smaller to bigger projects so for

example you're going to start off first

by doing lots of exercises so you can

get good with how arrays work objects

variables etc then you're going to build

little projects like a tip calculator

then i'll show you how to learn apis and

make an app that gets a random dog every

single time you click it you'll learn

how to build your own superhero apps if

you search up batman or thanos you can

actually find your superhero and you can

switch it up pretty cool pretty

impressive and you can show it off to

your friends i'll also show you how to

deploy these apps so they're online

anybody can use them at any time you'll

learn how to build your own weather app

with javascript i'll help you master

concepts like promises and async and

await some advanced concepts as well

right don't worry this is for complete

beginners okay so if you're a complete

beginner you're in the right place and

for even more intermediate there's going

to be a couple of things for you to

learn you're also going to build a

fighting game which is going to be

really cool it's going to be like street

fighter but you get to build your own

where your characters will have attack

and heal and there's going to be sounds

and graphics and you'll see how to build

that with javascript and you'll be

building the netflix app with javascript

so how freaking exciting is that i hope

that this is the most exciting

javascript course that you've ever come

across and i think you're gonna have a

lot of fun so stick around this is gonna

be a fun ride now before we just jump

into it what i want you to do is smash

that like button so this course goes out

to as many people as possible and as a

way to thank you here's a picture of a

koala bear alright and a baby and a

monkey there you go hopefully i earned

that like now make sure to click the

link that says join.replay.com

cp dash javascript we're popping it up

on the screen right now this is the most

important part of this video so click

that and make sure that you fork this

rupple it's going to bring you to this

screen right here and then what i want

you to do is you should see javascript

course by clever programmer right and

then what i want you to do is make sure

to hit fork this is very important okay

hit fork rupple and once you do that you

can actually get started working on this

course but this is the most important

step so click the link below in the

youtube description or somewhere on the

screen and then fork ruppel this is a

rebel that you need to fork and then

you'll be able to get started now once

you fork it it should bring you to this

screen over here now

there's a bunch of code already here so

that might intimidate you but don't let

that intimidate you okay you can pretty

much just ignore everything and when i'm

gonna be coding along in the tutorial

you can just follow along in this file

your playground.js

and you'll be completely fine you don't

have to worry about anything that's

happening in here right now

these are only resources available for

you as lessons

notes exercises and projects that you

could refer to later for now

this is pretty much the your

playground.js file is the one that you

should be using

in the video you'll see me use

playground.js but that's mine so don't

you you can go inside of it but don't

use it okay only use your playground.js

and write all of your code in here and

you'll understand everything that's

happening now just to explain to you

what this is over here and what is

happening is

there's some in here we have the

repo the github repo for this exact

project so you can go ahead and you can

fork that repo okay or not fork but like

you can star it all right you could

start that repo

um just so on your github you could find

it easily and plus it's nice for me to

have stars right for these repos and go

up and other developers can find it and

helps them

all right and then you have lessons so

in lessons for example

you can go to one of these lessons where

maybe i have this little app that shows

you how to click in with javascript and

get these squares right and clear the

game and you can go play it and then you

can go and look at its code so for

example for that red yellow green

squares app that i have right here which

you're going to build inside of this

tutorial on the left hand side i'm going

to have

its code available for you so inside of

dom i have this thing called red yellow

green right and

that's gonna be that's gonna have the

code to this entire app so you're

actually able to even click into it boom

and see all of the code okay but again

right now i wouldn't worry about looking

at that right now just stay put all the

project solutions are here so for

example there's going to be project

exercises and then you're going to see

project solutions so what are these if

you go into a project solution like

let's say

uh fighting game or weather app or

create netflix these are the final

completed versions of the app so if i

type in las vegas and hit search boom my

app shows up but if i go inside of

project exercises weather app these are

the uncompleted versions so when i hit

them you'll notice that the javascript

part is not working that's going to be

your job to do and

by the time you're going through this

course you'll learn how to do all of

this by yourself okay but for now don't

try to do this yourself i'm just showing

you kind of what's happening here what

is all of this and how the course is

structured but simply put for the rest

of the video all you really need to do

is just relax and follow along over here

in your playground.js

so whatever you see me do in the video

just replicate it here and we'll start

from the very first line of code hello

world what i've decided to do is package

all of this up into a course so you

could binge this like netflix and it

could actually keep track of your

progress and everything will be much

more organized and in one place in one

course instead of you having to watch

this on youtube so i've done this for

your convenience to turn the ultimate

javascript course for beginners into a

packaged resource for you and it's also

completely free and all you have to do

is just go to the link below in the

description that says

cleverprogrammer.com slash js dash

tutorial just go to that link click in

the description below i'll take you

directly to this completely free course

all you have to do is just sign up okay

it's gonna ask for your email or

whatever to create an account so i could

keep track of everything that you're

doing and then boom you will have

complete access to this course it'll be

in your library you'll be able to go to

cleverprogrammer.com and access it and

it'll track your progress it'll track

every single thing that you're doing so

it's very important i highly recommend

that you do that because it's going to

enhance your experience of discourse

with that said let's jump right into the

video all right let's get started with

the very basics of javascript so i'm

gonna assume you're a complete beginner

then we're gonna work our way up and

make it more complex okay so let's start

with something really really simple and

we're just gonna start with the hello

world and i know that's what everyone

talks about but let's do it anyway okay

so let's just do hello world and you can

hit command s or control s if you're on

windows and as soon as you save you'll

notice that it runs right over here okay

or you can just hit that play button at

the top and as soon as you hit that

you'll see hello world here will pop up

so perfect that's exactly what we want

now you can console log anything and

they'll show up there okay so try

console logging your name okay so try

console logging that and if you do that

correctly it should show up right over

here and don't forget these apostrophes

right here so let's give that a try i'm

going to put my name here i'm going to

hit run and boom at the bottom you see

rafa kazi so good job so far you're

making great progress and you most

likely got this right as well so good

job if you didn't that's okay don't

worry we'll you'll have plenty of

chances now let's do some programming

and let's make it simple and get started

with it okay so

what can i do as a programmer right what

are the things that i could do with it

so let's say we have a variable and we

start storing stuff in there okay so for

example i can say name and i can say

name is rafikaze and now if you hit run

you'll notice that this won't really do

anything this didn't do anything and i'm

going to or actually let's say name is

peter pan so this could my name can be

different from the name that i gave here

and you'll notice i don't see peter pan

anywhere so what's going on why am i not

seeing peter pan well what i need to do

is remember i need to console log it so

i can actually do this here and run it

and boom all of a sudden notice that i'm

seeing peter pan so that in javascript

are called variables so you can store

values in them and then you can refer to

those values even if those values are

really long so for example see i have a

sentence here and my sentence is how are

you doing today nice to see you hope you

have a great day whatever my sentence is

yeah and now if i do console.log and i

do sentence and we run this look the

entire sentence gets printed out but if

i remove this console log boom you see

that at the bottom right there no

sentence shows up so this is something

nice to kind of note and to pick up on

what you just learned about are

variables and if you ever see me doing

these two slashes this just tells the

computer hey this is for humans so don't

actually try to run this because if i

remove this and i try to run this i'm

going to get some type of error that's

going to say hey you haven't defined

variables which just means i never told

the computer what variables is i never

did something like variables equal to 5

or whatever but this line wasn't meant

for computer anyway it was meant for a

human being so these are called comments

okay comments and they are meant to just

be read by human beings and the computer

decides to completely ignore them now

let's do something where we have numbers

and other things okay so i want to show

you other things that you could do with

javascript so let's say we have food and

i set food to you know let's say you

paid maybe 20 for your food okay great

well i'll give you a little exercise

here i want you to go ahead and console

lock that can you make food pop up here

give that a try i'll give you five four

three two one let's go so we're gonna do

console log and i'm gonna say food just

like this and now when we hit it you'll

see at the bottom i see 20. okay

hopefully you're seeing that on your

screen now i'm going to remove this line

let me show you how you can do other

things with programming okay so for

example there's certain things called

operators so we want to tip let's just

say 20 okay now with that food and that

tip what we need to figure out is how

much is the tip because yes this is 20

but what's the tip amount so let's

calculate the tip amount and we're going

to say it well that's simply food right

multiplied by the tip so this maybe we

can call it tip percentage so we should

give better variable names and that way

things are much more easy to read now

before we run this remember this tip

here we updated it to tip percent so

make sure you copy paste that there so

use food multiplied by tip percentage

now you have your tip amount okay so

let's now print that out so i'm going to

say tip amount and let's try running

this and we see that it was four dollars

okay very good that's exactly what we

wanted now let's say we want to make it

a little bit more interactive and we

want to make this a kind of like an app

experience so right now i hope you're

excited because you're going to be

building your first app with javascript

that's the power of javascript you can

build things with it so freaking fast

and you're going to be building an app

right now so i'm going to teach you

something called you know basically how

to get inputs from user that's how you

make apps because right now we've hard

coded food to b20

but let's say that if the food is a

different amount well you'll need to

come to this app that you made and

you're going to need to put 40 here and

you're going to need to put a different

percentage you need to calculate this

differently every single time it's going

to be kind of annoying now here's how

you can use user input okay so instead

of this food saying 20 here kind of hard

coded here what i'm going to instead do

is i'm going to say prompt

okay and

i'll show you actually how prompt works

so let's go ahead and try that first so

i'm just going to say we're going to

create a variable called banana and

we're just going to store something in

there and i'm going to say prompt or

let's say fruit okay and we're going to

say what is your favorite

fruit we need to console log this so i'm

going to say console.log we'll say

all right and i'll say

my favorite fruit is mango this time

right and boom you actually see mango at

the bottom right that's exactly the

experience we wanted for this app so

just very simple but we need to make

this happen and we need to make our food

calculator thing that we made more um

dynamic because right now it's hard

coded so we need to make it where it

takes an input from the user instead of

saying 20 here all right and then it

calculates the tip amount based on that

so what can we do i want you to take

about 30 seconds to a minute and see how

do i make this food thing over here

interactive if you haven't figured out

so all good let's do this together so

i'm going to say prompt and in this

prompt i'm simply going to say how much

was the food and we don't we don't want

this fruit line to run so i'm going to

comment this out by putting a slash

slash here and i'm also going to comment

this one out this console log by putting

a slash slash here because i don't want

those to run i just want this here to

run so what's going to happen now is

food is going to run it's going to ask

for what how much was your food once you

put in how much the food was it's going

to store that inside of the food and

then our tip percentage is going to run

and then our tip amount is going to be

calculated based on whatever you put in

the food multiplied by 20 tip and then

we will output the tip amount perfect so

how much was the food we will say was

let's say forty dollars i'll hit run

let's try it again and let's say it was

twenty dollars so twenty percent of

twenty should be four let's try it boom

so that was great and there we go so our

food was calculated properly we do have

four here very good now what if you

wanted to make tip percentage

user input as well where this is not

hard coded this is the data the user

puts in because the user can decide hey

how much tip do i want to add do i want

to give 10 tip 20 tip 1 tip 100 tip that

should be up to the person and what we

want to do is the user should be able to

put in let's say they want to give a 20

tip so this should be able to put in 20.

the user shouldn't have to say 0.2 right

so they should be able to go 20. now

what do we have to do to get 20 down to

0.2 well 20 divided by 100 gets that to

0.2 so it's whatever the user input is

we divide that by 100 so let's replace

this by user input let's say for example

but in this case you know what we can do

is we can just replace this with prompt

okay and we can say

let's just say tip percentage okay so

that's all the prompt will say and then

whatever tip that they put in we will

divide that by 100. all right so here's

one cool thing that we can do on the

bottom right here click right in front

of that arrow and it'll allow you to

write code that will run right away so

you could see what's happening so let's

say that i have 20 and if i divide that

by 100 and then i want you to hit

execute at the bottom right and uh

scroll all the way down and you can see

20 divided by 100

is 0.2 right so that's exactly what we

want so that's how that division sign

works and i know i haven't shown you

division but

there are a bunch of things that we

could use in javascript so there's

multiplication there's division there's

exponents there are a bunch of other

things but like plus minus right all the

basic math stuff works so let's try and

see if this is working this food thing

that we're making here okay so

whatever the tip is we're going to

divide that by 100 and then we're going

to multiply food with that tip

percentage all right so let's give that

a try over here i'm going to hit run and

let's see what happens so how much was

the food so let's say i paid a hundred

bucks for the food the tip is going to

calculate okay it's a tip percentage all

right let's say we want to give 10 as a

tip so that would be 10

and boom you can see that it actually

says ten dollars right there now if you

don't even want this to come in the

console and you want this to come like

where the user could see it you could

even use alert and you could alert the

user with what the tip amount is gonna

be so let's try this whole thing again

and watch what's gonna happen it was a

hundred dollars um how much was the tip

it was let's say 10

and boom it just says right there you're

looking at 10. i'm just going to comment

this out normally in a normal app you'll

never use prompt to get user input

you'll use something called forms in

javascript or you know html forms you

use forms and users like we'll put in

the data there and then that'll populate

in here but for now we're just going to

stick to using prompt because it's the

easiest way without having to do too

much html and all this other crap all

right so all right now what if we want

to do something more because right now

this is pretty good right but what if we

want to show the tip amount and like the

total amount right what do we want to

show how much the food was how much the

tip was and then what's the total amount

what if we want to show all of those

things so let's go ahead and do that as

well so we're going to say total okay

let's create a variable called total and

total will be whatever food was plus the

tip amount so let's go ahead and do that

i want you to take a try and do that

yourself and then console log it see if

you nail it so take five to ten seconds

to do that right now count down five

four

three

two

one

and now let's go ahead and let's do it

together all right i put myself up here

so i'm nice and out of your way so let's

go ahead and do this together now so

total is gonna be food plus tip amount

and then let's go ahead and let's make

sure the console log and i'm gonna say

total and then let's print it how much

was the food okay so let's go the food

was 100

how much you want to tip let's say 20

so that should be 20 so it should be 100

plus 20 tip that should put you at 120.

so let's see and we got this weird thing

so what's happening here is if you take

a thing like this 100 and you try to add

20 to this this is not going to do what

you think it's going to do okay because

this is a different data type and we're

going to talk about different data types

so i'll write this here for now data

types and there are different data types

like strings and numbers and then other

ones anything that has these quotes

around it is a string and so if you try

to add two strings watch what's going to

happen when i hit execute it's going to

add a hundred plus the word 20. so it's

almost like you're adding words together

okay it doesn't see these as numbers

it's like looking at it like a word this

is a word you're spelling 100 and when

you try to add those two words together

it makes them one word and so that's not

what we want but if you take a number

100 and then you add 20 to it and if you

hit execute you can see that that

actually gives you 120 basically what

you're looking for so what we need to do

is we're getting this data from the

users and it's coming back as a string

you guys so for example i console log

this food right here and let's just like

run through this and let's just say 100

and we'll say 20 and run this that first

100 even though you can't see it it's

actually a string so this is not a

number it's actually a string so what we

want to do is we want to force it to be

kind of a number so let's say i have a

100 here right if i want to force it to

become a number i can call this i can

wrap this in something called number so

number is a function and it will take

this 100 and turn it into an a regular

100 without the quotes so we'll talk

more about functions later so we'll make

a note of this we'll talk more about

functions later things like that and you

know maybe even type casting but those

are a little bit more advanced right now

i don't want you to worry about any of

that i just want you to focus on i'm

just wrapping this thing in something

called number and it automatically takes

it from a word and turns it into a

number and so i'm gonna take here and

i'm going to just wrap this in a

function called number like this so when

you get food amount that should be a

number and this tip percentage here that

should be a number as well so i'm going

to wrap this into a number as well just

like this and we're going to move this

here so you can see this very clearly so

i've wrapped this inside of a number and

i've wrapped this inside wrap this

inside of a number as well make sure you

have the right amount of parentheses

going on so now we're not going to get

that weird error anymore let's go ahead

and run this again we're going to say

the food was 100 tip is 20 percent and

it calculates it correctly over here and

you do see that it says 120 okay that's

exactly what we were looking for

perfect now one other thing that's kind

of confusing when we're looking at our

console log is like ah this says 20 here

and it says 120 and

i would want to label it right so i

would want to want it to say tip amount

here and then 20 and then total here and

then 120. in other words like basically

i wanted to say

tip like that here and i would want this

to have total here just like that right

that's that's the the thing that i want

so let's do that here so in console log

i can actually say tip amount and then

here i can say total so now watch what's

going to happen when i run this and we

say 100 and we said 20 is it tip amount

20 total 120. okay so now it's kind of

nice our app is working in a better way

a nicer way so everything looks cleaner

and better and it's just showing you

different things you could kind of do

with the console log so i hope for now

this was really good we're gonna keep on

going there's a lot more to cover i hope

you're excited i'm excited and i'll see

you shortly alright let's get back to

coding and now you're gonna learn about

some really cool stuff and we're gonna

build some more fun stuff okay so let's

go ahead and do it together but one

thing i want to tell you is if you want

to code yourself you're going to be

coding in a file called your

playground.js okay so that's the file i

want you to be using when you're coding

right now because i'm coding in a file

called playground.js okay so by the time

you're seeing this video this file will

have like all the code that i have

written you know so far so this is going

to have like pretty much everything that

we have done together but in your

playground it's like your scratch file

and you're able to kind of code along

with me all right let's keep going let's

talk about a couple more things okay so

one of the things i want to talk to you

about are like different kind of data

types that we have all right so we got

numbers all right and the examples of

them are like 1 5 10 100 you know

whatever you could have decimal numbers

too like 2.5 you have other things like

what we call strings and these are

anything that have quotes around them so

it's like if i say hello or if i say

what's what is up okay those are all

strings and now strings could have

single quotes around them or they could

also actually have double quotes around

them okay so like this you know as long

as they're wrapped up and

it's even on both sides okay single

versus double they both work so those

are strings so something we were talking

about up here anything in quotes is

going to kind of print out exactly like

how you want it to okay other data types

might include things like arrays and

we'll talk about them later i'm just

going to kind of leave a note here for

now for this we also have objects

a different completely different data

type another data type is boolean so

this is either something is true or

false okay so true slash false this is

an example of a boolean and why i'm

talking about this and i know right now

it might be like why are we talking

about data types i mean this seems kind

of boring but this is going to become

really important because imagine if

you're building an app where you know

let's say that it's a simple app and it

says hey if raining outside tell the

person to get an umbrella or if it's not

raining outside then tell a person to

get a sunglasses well you're going to

need to understand how boolean works

otherwise you're not going to be able to

make an app like that work taking it

into real life well banks work off of

booleans right because if you think

about a bank can you take out if you

have zero dollars left in the bank can

you take out uh 10 000 or 1000 dollars

you can't so the bank has a line of code

that's sitting there that goes if user

has this amount of money available so

let's say you ask for five thousand

dollars it says does the user have five

thousand dollars available and if the

user does then great let them transact

it then basically if they do say true

but if they don't say false okay and so

using booleans you're able to do

something we'll talk about later you can

do conditionals and then you can do if

else type of statements or if then and

that's going to be important another

thing i want you to learn about is well

you know we have data types but one

other thing we need to worry about is

like basic math stuff okay and it's

gonna be really simple like i'm gonna

say like first grader level math stuff

okay or third grader level like

something really really simple so let's

go and just talk about kind of math like

operations that we have okay and you

should know about these so for example

we have multiplication so you can

multiply using this you can divide using

a slash you can uh do other ones like x

exponents okay and these are like with

two asterisks like this and then

you know we have modulo which is like

this or you know in other words is like

a remainder okay so for example if you

did five modulo two what would you get

well that's a great question let's

actually ask our javascript here so i'll

do five modular two and hit execute okay

and you can see that one is the

remainder here right so you'd get back

one if you did this so that's how modulo

and remainders work and then of course

you have add which is a plus sign which

is pretty simple and i don't need to

probably give you an example of that and

then you have minus okay so these are

kind of the majority of the math

operations that you will do when you're

coding so these are helpful for you to

know because when we're we're going to

be going along and we're going to be

building things together and some of

this stuff you're going to kind of need

to know so we're going to just put it

out there let's go ahead and call it

math operators because they're like

operators okay and then i'm just gonna

show you a couple of like

math

methods okay that are gonna be helpful

for you so and one of them we can

actually even use right now so floor and

seal the floor it just rounds down okay

and this just you know if you can guess

it by the name it rounds it up if you're

getting a tip well that's that's going

to be really weird right because like

let's say you haven't placed an order

and it was for

110.25 cents or something and then

you're trying to calculate a tip on that

20

and then you get these like decimal

numbers now sometimes that could be

confusing and maybe you don't want it to

a decimal number you want it to be an

exact dollar amount okay let's just say

well what you could do in that case is

you could take a number like 22.5 or

110.25 cents and you could call floor on

this okay so we're going to do

math.floor and we're going to wrap this

in and i'm going to hit execute and you

can see that it just floored it so it

just rounded it down that's all it does

so if you did the same thing let's say

seal and i said 110.25

and i hit execute it would round that up

to 111 okay when we're actually building

our we're going to be building some

games in this tutorial as well so for

example later when we go and let's say

we build rock paper scissors or we build

any of these games you're going to need

to know some of these things okay so you

can round down and round up um and

you'll see why so you need to know this

if you want to build those games later

and then there's random okay all right

so here's how random works okay this

gives you a random number okay okay so

this is how you actually use math.random

okay so let's say i use math.random

don't put anything inside of it and just

run it so it'll always give you a number

between 0 and 1. so if i keep pasting

math.random you'll always get a number

between 0 and 1. now if you want to try

to get a number between 0 and 3 just

multiply this by 3 like this and this

will always make sure that you get a

number between 0 and 3. and so if i keep

running this you can see i got

math.random multiplied by 3 and there

you go i got a 2.4 let's try it again

right i get a 0.42 and now you know when

you're playing rock paper scissors you

want rock to be zero you want paper to

be one and let's say you want scissors

to be two so if you want those numbers

to map to them like that you need to

pick between zero one and two okay

that's what you need to do that's why

you need to run this function and i'm

gonna you're gonna learn later why

that's the case okay but that's why you

need to get between zero one and two so

if we keep going with this well let me

ask you this right right now you're

doing this and you get this long number

two point seven two blah blah but you

just wanna get either zero one and two

so in other words how could you turn

this long number into just two okay take

a couple of seconds it's one of the

things i've already taught you okay hint

hint it's one of the methods you have to

use here okay so see if you can guess

this i'll give you five seconds five

four three two

one

all right let's call math.floor on this

and wrap this in and hit execute and

you'll see boom i just got two so then

in other words what i have to do is i

have to copy this math.random multiplied

by three paste it here and

call

math.floor on this entire thing so now

when i do that what will happen is this

will eval run and evaluate and give me

something like two point seven two point

seven eight nine five five five four

four four some long number right two

point seven nine blah blah blah and then

on that it'll call math.floor and it

will turn this into just two and you'll

end up with just two okay so let's try

running this boom i got zero perfect

let's run it again boom i got one let's

run it again boom i got zero let's run

it again boom i got two perfect so i'll

always get between zero one and two

those are the three different choices

that'll map to my rock or paper or

scissors later on when you're coding

that up so that's just an example of how

these methods work we'll practice more

with them later but right now you should

just know them and have them in your

notes all right guys and let's do this

thing right now so let's just go up and

comment out like some of this stuff here

so like we don't want to run this

anymore so what i'm going to do is i'm

just going to go ahead and highlight all

of this okay because i don't care about

running this anymore because otherwise

every time you hit run it's going to

keep prompting you and we don't want

that anymore and just hold command and

then hit slash or if you're on windows

probably hit control and then hit slash

okay so let's do that and it should

comment out all of this okay with

exactly how i did on my computer if it

doesn't do that for you just turn it

into a comment block but just make sure

to close the comment block okay because

if you don't close it then everything

will turn green and that's not what you

want either so i'm going to hit undo and

i will just leave it as let's go back up

here and i will just leave it as a

common block like this okay and now

let's go back down to where we were at

all right so one of the things i'll do

now is let's go over to our

console here okay so let's go to boom

let's go to this guy over here okay and

i'm gonna drag hit settings and there's

display size and i'll make the display

size bigger let's go all the way back

hit console perfect so now we have some

more room to see everything here easier

fantastic

all right so

we covered the math methods we covered

math operators we covered some of this

data type stuff right so let's go back

up to our variables here okay so in our

variables introduce to this so you have

var

const and let these are three very

important things i want you to know and

normally when you make a variable you

never just make it naked like this you

always either call it like you say let

sentence equal blah blah blah let so you

always just put a let here so right now

i will just tell you never use var okay

i'll make your life simple you can use

const or let only use const if you know

that thing that you made you're never

gonna change it again but if you're

gonna change it use let so most of the

times for now at your level i will just

say use let okay that way you won't run

into any problems so for simplicity use

let but if you want something to be

constantly true then you're gonna use

const so all our variables just put a

let there and for more advanced users

we're learning javascript what this does

is it makes sure that you don't have a

global scope for your variable names

okay it gives you kind of get scopes it

down so let's go down here now let's go

ahead and like let's do something

simple okay so i'm going to show you

programming in a fun way as if you were

sitting right next to me and we're just

coding up something together okay and

i'm like yo let's walk through this

let's say

we make like a tiny little weather app

okay so let's go ahead and let's make a

baby weather app and uh what we're going

to do is we're going to say if there's

rain then what we want to do is we want

to say grab your umbrella or

just print the umbrella emoji

and if you don't have an emoji that's

fine you don't need an emoji okay this

is just for fun if it's not raining

we're just gonna say wear

your sunglasses okay so it's gonna be a

simple app where the user is going to be

asked if it's raining or what the

weather is and if the user says it's

rain right now then you tell them grab

your umbrella and if the user says

anything else like it's not raining or

it's sunny outside then it says hey wear

your sunglasses okay very very simplest

overly simplistic baby level app but

just to kind of gives you the ropes of

programming okay so let's go ahead and

build this out now and we're going to

introduce you to a concept called

conditionals they're your friend they're

so freaking awesome and they allow you

to build amazing apps and amazing things

all right so i'm going to say let

weather so i'm going to create a

variable called weather so whether it

could be rain it could be

sunny whatever so we'll just say if

weather weather rain then i want you to

console.log grab your umbrella just like

this i'm going to copy this and i'm

going to paste it else we're going to

console.log and then the sentence is

going to be where your sunglasses and

i'm going to paste that right here so

make sure that you copy this correctly

so here you have if weather is equal to

rain with the two equal signs very

important okay and i'll explain that to

you later why as well okay so this is

something called you have conditional

operators and those include conditional

operators include things like equal

equal sign or equal equal equal sign or

greater than sign or less than sign or

less than equal to or greater than or

equal to not equal to not equal equal to

and those are the main ones that you're

going to use okay i'm just leaving this

here for you to know we're using this so

if the weather is rain this is going to

become true if this weather here is rain

so this weather here is rain this is

basically going to say hey is it rain

equal to rain let's test it let's see

what it says so is rain equal equal to

rain and let's hit execute and let's

watch what happens and boom look at that

it says it's true now let's say is sun

equal equal to rain it's going to say

false okay let's try a couple of others

5 greater than 2

is that true or false

all right hopefully you guessed it

correct let's hit it and you can see it

says true okay is 5 greater than or

equal to 5 is this statement true

greater than or equal to 5 yes it's true

because 5 is equal to 5 okay greater

than or equal to but if you do 5 is

greater than 5 this will give you false

because 5 is not greater than 5. so

these are a couple of ones that you

should know and learn about because this

is going to be really important for any

app that you're essentially building

okay so if the weather is equal to rain

so if this is rain because this weather

here is rain if these two are equal

what's really going to happen is this

entire thing here is going to evaluate

to a true statement so this entire thing

is going to become true and if something

becomes true an if then statement it

will run this line right here but let's

say that you put false here well then

it's going to run this line right here

and it's not going to run that line okay

so that's how if else statements work

just make sure you have the right

squigglies so this squiggly opens here

and closes here that's where your

true statement goes the l squiggly opens

here closes here and that's where your

console log this is where your false

statement goes so let's hit undo undo

undo and go weather is equal to rain so

now what i'm going to do is we're going

to hit run and let's see if this runs

how we want it to it says grab your

umbrella beautiful so because weather is

rain well what if the weather is sunny

before i hit run

do you think it's going to run line 57

or do you think it's going to run line

59 which one do you think it's going to

be take a second

and let's hit run and let's see what

happens and boom it will run this line

because this statement it found it was

false because sunny is not equal to rain

so this becomes false so then it won't

run the true statement it will go ahead

and run this false statement okay

under the else

so if we want to make it a app that a

user can use

this input here we will make it

something the user puts in so remember

how do we ask a user what they want to

put in do you remember it starts with a

p and then goes p r o

hopefully you remember that was the word

prompt and we're going to prompt the

user and we we're going to going to ask

how is the

weather you know so if it runs

boom how's the weather and if we say

it's

rain

you're going to see that it says grab

your umbrella

if we say something else let's say it's

sunny it's going to say wear your

sunglasses so it's working exactly how

we want now if the weather is equal to

rain that doesn't really make sense

right let's make let's put a y here so

it checks for for weather is equal to

rainy so let's run this again

and now i'll have to put in rainy here

so let's put rainy and now it will say

rainy equals rainy this is true and then

a little console log

grab your umbrella so we just made a

mini app that can

you know fake help you

with uh what you should do

based on the weather okay if you wanted

to make it a fancier app or a more real

world app you'll be put at pulling the

weather data from a real app so you'll

be pulling it from some real app using

an api

and then you can detect what the weather

is automatically and then if it's

raining

instead of console log grab your

umbrella instead of this you could have

it send you a text message on your phone

saying hey it's going to rain today take

your jacket with you so you could use

twilio to send you literally a text

message sms on your phone so that's

freaking mind-blowing right so that's

really the benefit of uh learning this

and right now i know these are like baby

applications we're making and you're

look oh i just want to make something

bigger please hold on we're going to get

to it we're going to build a lot of

amazing applications but let's start off

and keep it simple and so far you've

done a fantastic job let's keep this

going all right welcome back so we're

going to talk about functions now you we

just got done making this baby app what

we're gonna do now is i'm going to just

essentially comment out this entire app

okay because we don't need it all right

now that it's commented out i do want to

let you know that on the left hand side

when you're using this rupple there will

be something here and right now this

folder is called notes it might change

later but what you'll be able to do is

you'll be able to go to this folder and

pretty much everything that we cover in

our playground will be kind of organized

here as notes so even though it's like

commented out here and kind of hard to

see because this file is going to get

really messy as we start to code and

build more and more things here you can

go here miniweatherapp.js which

essentially has that exact app that we

created and it's just kind of sitting

here for your use okay so this code will

always be there and available for you

i'm gonna go back to my playground here

but if you're trying to code along

you'll be going to your playground okay

this is going to be your playground so

make sure that you go to this all right

so let's talk about functions because

functions are a pretty important part of

any programming language and for

javascript they are massive so

let's go ahead and learn a little bit

about functions how do they work well

functions are designed to basically run

a recipe so they can run multiple things

for you at once and it also organizes

your code in a nice little way okay and

so functions make your life a lot easier

so let's go back here so you see how

when you create a variable like a

variable it can only store

like a name or something along those

lines what's cool about a function is a

function can store

blocks of code

so for example remember this food app

that we made earlier i'm just going to

go ahead and comment this out this app

that we made earlier i mean this is a

lot of lines of code and if i ever want

to run this app i have to always

uncomment these lines of code or

basically write all of these lines of

code every single time i want to run it

whereas

imagine that it was in a function well

then in order to run this piece of code

all i would have to say is i wouldn't

have to uncomment all of those lines up

there all i would have to say instead is

i could just go run a function that you

know says

calculate tip amount and then i would

just give it its tip because okay so

let's say that there was a tip or you

know maybe the amount of food was a

hundred dollars i just gave it that and

then the entire app automatically runs

just by me typing in this instead of

that entire chunk of code so that's

where function comes in so let's go

ahead comment out this entire block

again with command slash or control

slash and i'm going to go down here i'm

gonna remove this line i'm gonna start

writing our first function

so i'll write a first function what this

will do is it will make a greeting okay

so or say my name so let's do a say my

name function okay so let's do say my

name

and say my name function it will do

console.log and it'll just say qazi

because my name is qazi okay so that's

all it's going to say well let's go down

here and i'm going to call and i'm going

to hit run and you're going to see that

nothing really happened right it didn't

actually do anything and to make things

less confusing let's also comment out

everything that we have here so we just

have everything commented out i'll run

perfect so we see nothing in our console

nothing happened well why didn't it do

this so even though i made this function

i have to call this function like this

and now when i hit run watch what

happens boom you can see that it says

qazi right over here awesome now let's

go on and you know we've done a pretty

good job with this function say my name

and look at what it does though before

we continue and move on this is how you

call a function so unlike a variable

when you call a function you put open

and close parens in front of it okay now

this function

what it the name of it is say my name or

the variable of this function right is

say my name this is the name of it and

when you call it it runs all the

instructions that are inside of that

block okay so for example what does that

mean what if i had like console.log

seller name and say brian

and let's also have it say banana

whatever right if i run this you're

gonna notice that by just calling the

function it is running all these four

lines of code and it runs them all right

see that and then watch what happens if

i just comment this out and i run it

boom nothing

so now all we have to do to run our code

is we don't have to comment or uncomment

the entire thing we can actually just

comment or uncomment that call of the

function okay this is called

calling your function so whenever i say

call your function that basically means

you write the name of the function with

open close parens cool

now

let's say that we want this function to

be more dynamic because right now it's

just saying quasi-raphael brian banana

so it will never actually say your name

right

so what how can we handle that how we

can handle that is actually let's remove

all of these lines right

and

we're gonna say hey we want you to say

like a dynamic name that the user gives

you okay well it's gonna go hey i don't

know what name is in this case what

we're gonna do is we're gonna also put

that here so this function say my name

okay has an argument

called name and it's logging that

that argument out okay so then if i say

quasi here and i run this

it's going to print out quasi it's going

to log out quasi but what if i say lance

here what is what is it going to do

let's try it

and boom lance because i call this

function okay

and here's how it works it goes here and

it puts in the name lance

and then it goes here and puts in the

name lance and logs it out to the

console that's how

a function

works okay this is a function with one

argument so let's if i take you back to

our older function that function has no

arguments okay let's make let's copy

this and let's paste this here okay and

then let's make this the dynamic one

all right

say my name yeah so this is say my name

with no arguments this is say my name

with an argument okay let's give them

different names maybe so this is say my

name maybe let's just call it say my

name two for now okay to call this

function what are you gonna have to do

so if you wanna call this function right

here say my name to

how will you

call it okay take five seconds and see

if you could call it okay and i'll give

you a hint it's what you did on line

seventy

five

four three two one

all right let's do it so i'm gonna say

say my name

to

and in this i'm actually going to give

it a name i'm going to give it an

argument

and you can see that now it will print

out kazur if i say kevin

and run it you'll see that it'll

actually say kevin right here okay and

we'll comment outline 70 where it says

say my name because we're just running

the function that we wrote on line 72

and there's a nice little toggle that

you could toggle to

and it'll basically just

collapse everything that you have inside

of the function okay

so that's kind of a nice way to do

things so moving forward pretty much

everything that we do

will majority of the times do it in a

function it keeps your code clean

concise compact and it's just a better

way to do things and we'll we're now

going to step it up

and make things that are a little bit

more advanced and do them with the

function okay so let's do that next so

i'm gonna comment out this line here say

my name

two okay i'm gonna comment that out

let's go down let's make another

function

and we'll call this function greeting

okay so greeting

will take in

um

your name

okay

it'll ask the user it'll basically need

the name of the user and then what

greeting will do is it will say well

console.log it okay and it'll basically

say hi

name

nice to meet you okay

and if i run greeting so watch what's

going to happen so let's say i run

greeting and i give it my name and i say

my name is quasi and let's run it and

let's watch what happens okay it says hi

nice to meet you

hi name nice to meet you but that's

weird it says name here and it

says exactly name that's not what i

wanted to say i wanted to say qazi so

how do i do that

um

what we're going to say is

hi

plus

name

okay and watch what happens so that

allows you to concatenate strings

together the plus sign so watch if i

have hi

and then i put a plus sign here and i

say

kazi

and if i hit execute you can see it says

hi kazi

but it's saying it right next to each

other so we want to have a little space

in there so i'm going to say hi space

plus kazi like this okay so this is high

and then one empty letter empty space

here hit execute now it says high quasi

with the space

in the middle

okay

perfect

so

we're gonna go hi

space plus name plus

all of this stuff that we wrote here

comma nice to meet you so let's put that

there okay this will concatenate and get

our greeting ready so we'll say greeting

is equal to

or we'll just say greet is equal to that

okay and then in console log we'll just

print out whatever greed is so let's hit

run and you can say hi kazi nice to meet

you well what if i change my name to

lance

it will go

high lance nice to meet you so it's

working as expected that's really good

but it still doesn't look super

nice how this is with the plus sign and

it's kind of annoying you have to like

put this space there and it just feels

unnatural so

this is why i want to show you template

literals because they make your life a

lot easier so instead of this code

saying greedy is equal to blah blah

let's write it in template template

literals okay so let's go greet equals

and when you do template literals you

always have to do these backticks on

your computer okay so you always start

off with the backticks okay so let's put

a backtick here so template literals

now what i'm going to say is

hi

name comma nice to meet you and we can

make this name dynamic and how we're

going to do that we're going to say this

name is a javascript part it's not a

literal string so how we're going to do

that is we're going to wrap it in the

squigglies and we're going to put a

dollar sign whatever is wrapped inside

of the squigglies followed by a dollar

sign it will understand as actual

javascript okay meaning that now it's

going to put this whole thing together

kind of like how we were doing here but

it this just does it in a much nicer way

so now let's do console log great and

watch what happens so i'm going to hit

run hi lance nice to meet you what if i

say

amber heard haha

you guys saw what has happened right the

news is out or johnny depp okay let's go

here by the way which side were you on

were you on amber heard side or johnny

depp site comment below let me know i'm

curious to know your thoughts i think

that

she kind of deserved to lose and um

you know it's nice that johnny got

he was awarded 10 million dollars she

was awarded 2 million

so basically she owes johnny depp 8

million dollars which is more than her

net worth so

she's not gonna have a lot of fun paying

that off uh but regardless that's

neither here nor there

let's get back to what you came here for

so going back to this okay i got my

greeting i can do johnny depp so it's

like hi johnny depp nice to meet you so

hopefully you understand how this

function is working so let's go to the

semi name function right this is a

function called say my name and it has

no arguments okay in other words it has

zero arguments so i want you to also

learn how to speak the lingo because

you're gonna start hearing this a lot uh

you know write a function call blah blah

and it should have x arguments so this

is it's a function called say my name

and has zero arguments okay

so i want you to write out the sentence

here for this one say my name too so

write out a sentence exactly in this

format

that talks about this and you could even

take this a step further and say uh like

what does this function do and you can

say it

prints out

your name to the console or it logs out

i'm just from the python world a lot of

the a lot of my life and so you say

print there a lot so it logs out your

name to the console okay so that's it

okay console.log quasi and so this is

like what the function does okay so it

does this is what it does

and you could write for semi name two in

the exact thing okay what it is and what

does it do actually try to pause my

video so you can write it in english

what you think this does the lingo is

important to understand okay so in chess

you have to learn something called chest

notation this is kind of like that but

for coding so then we have a language

that we can build upon and get better

every single time so take about five to

ten seconds i'll count down now or just

pause the video five four three two one

cool so here's what we're going to do

here this is a function

called okay the name of this function is

say

my name to it has

one argument and if you want to be extra

special and so you could say it has one

argument called name and then what does

it do

it logs out your name to console so it's

a good habit to get in

in later in life this habit if you keep

doing this right now will translate to

you writing documentation for your code

so one is gonna help you develop just a

better skill and two it's gonna help you

understand and develop the skill of

documentation and reading and

understanding the documentation which is

gonna be really valuable when you get a

job as a developer because you're gonna

need to know these things and that makes

you a lot more valuable that's what we

did for greeting okay this is what we

did for this greeting we introduced you

to the concept of template literals and

this is going to be very helpful for you

especially when you're making a couple

of games javascript games that we're

going to show you later like for example

rock paper scissors all right so let's

go ahead and move forward now all right

now we're going to create another

function okay together so because i want

you to constantly get a lot of practice

with functions okay and this function is

going to have multiple arguments so you

can actually have more arguments than

one okay so you can have one argument or

two arguments um or 10 arguments or 20

however many you want but generally

between one to five is like pretty you

know

reasonable and you don't really want to

add more arguments just for the sake of

it so let's go function and we're going

to create a function called sum and i

want you to try this out so it's like if

i want to have a function sum and it

will have two numbers that it'll take in

as an input okay so it'll have two

numbers that'll taken as an input a and

b and what this function should do is

return the sum of these two numbers so

you'll also be introduced to the concept

of the keyword called return okay

there's a special keyword in javascript

and generally with your functions you

never you don't really want them to

console log things you want them to

return things so you can do something

with them later so we're gonna start

getting in the habit of return and then

eventually you'll start seeing why

returns are actually helpful and why

they matter all right so let's have this

return a and b the sum of them okay so

we're gonna do return a plus b and i'll

i'll show you why we're using the word

return instead of something like

console.log and let me do that with a

simple example here so first let's just

run this function so when i do sum and

if i give it one and two it should take

one and two so it should replace a with

one b with two so it should do return

one plus two that's effectively what

happens so it should return can you

guess

three okay that's right so that's what

it should return but watch what happens

when i run this okay and let's um

comment out this greeting because we

don't need to run that anymore and let's

run this function well nothing went to

the console so it

ran something happened but nothing ever

went to the console interesting

well it's not being shown so let's go

ahead and show it so let's do

console.log and run it and now you can

see that it says three now watch what

happens if i do num1 and i want to store

this result somewhere so i want to do

one comma two okay so i want to store

the sum of one and two in a variable

called num1 okay so let's delete this

line now and let's run and it got stored

and now we'll we'll log it out so the

console.log and i'll say num1 okay let's

run it and it got the sum three okay it

stored three into this variable called

num1 and then we console log it out and

boom we see it right there now to prove

my point if we hadn't done return a plus

b instead imagine we just did console

log a plus b watch what what's gonna

happen let's run this and we get an

error and this error says undefined so

this prints out the console log right

but when we run

so this line goes and it goes 3 but then

this over here says undefined because

what's being stored in num1 is undefined

we don't have a number like three that's

actually being stored here we're console

logging something and we're trying to

store console.log here and you can't

store that so that's why what you want

to do here is return a plus b if you

don't do a return then this function is

essentially useless and it can't be used

in other places and do actual helpful

things okay so that's why what we need

to do is actually change this to a

return a plus b

just like this okay now when we do num1

it actually does get used okay let's

comment out both of these lines now and

what we're going to do is we're going to

go back all the way up to when we made

that little baby tip calculator thing so

i'm going to copy this entire thing and

we're going to turn this into a function

so i copied it okay from line 17 to line

24 and we're going to paste it here

right there let's hit run so nothing

should come out to the console so that's

perfect that's exactly kind of where you

should be right now now i'll go and

uncomment this and um

we won't be using these prompts anymore

because that's kind of uh you know when

you're using functions and prompts is

like rarely ever used it's kind of an

easy way to give a front end to the app

you know just kind of for you to play

around with but majority of the times

you wouldn't really use prompt that much

but first let's just focus on turning

this into a function so we're going to

say is going to be a function and we're

gonna call it calculate uh tip and food

amount something like that okay or let's

just call it calculate total food total

okay so this is gonna calculate the food

total with the food amount plus however

much the tip was okay we won't have the

alert statement anymore so let's remove

that and this function is dependent on

two things how much you paid for the

food and the second thing it's dependent

on is how much you want to give as a tip

so these two are going to be arguments

that we're now going to pass and so i'm

going to say food and tip percentage all

right so basically here's what we're

going to do right so tip whatever the

user gives we're going to take that tip

we're going to divide that by

100 okay so if the user says hits 20

then we're going to take that tip

divided by 100 and turn it into an

actual percentage which would be 0.2

and then we'll multiply this now we're

going to do the same thing for food

we're not gonna have this number

prompting anymore okay we're gonna

remove that we're gonna say whatever

food is gonna be whatever food is here

so in other words we actually don't even

need food because the user is just

passing that information down so

food is going to be a given tip is going

to be a given we're going to calculate

the tip percentage based off of the

given tip and then we're going to do the

same thing so take the food multiply by

the tip percentage that'll give us the

tip amount and then the total will be

the food plus the two amount and then we

can console log it out if we want to and

in this case since we're being adults

now not a little children anymore we're

going to do returns total

let's go here and let's indent this so

you can grab this and just hit tab

and make sure that this function has a

squiggly that opens it and a squiggly

that closes it okay that's pretty

important whenever you're writing

functions so i'm just hitting back or

you can just hit format at the top and

they'll automatically format your code

for you if you hit this and formatting

just means it makes it look nice and

pretty okay so i have calculate food

total it takes in food and it takes in a

tip so let's actually try this last

console log and we'll call the function

calculate food total and we'll say the

food was 100 and the tip was let's say

20

let's go ahead and hit run now let's see

what we get and we get back 120 so now

you can start to see the power of

functions that

they can do a whole bunch of things very

quickly and so you just call it in a

very easy way give it two inputs and

boom your function is up and running now

let's take this a step even further so

remember when we created a sum function

c if you can replace this line 104 okay

so you can leave the total here but see

if we can replace this and this instead

of using this plus sign here and see if

you can use a sum function to calculate

the total so i'll give you five seconds

you can pause the video and try to do it

yourself okay so let's go five

four

three

two

one

all right let's give this a try so let's

go here and instead of using a plus sign

what i'm going to say is i'm going to

say sum and we're going to give it food

all right so it's going to be the food

amount and then we're going to give it

the tip amount so now we're using the

function that we created ourselves

earlier and then we're going to store

the result of that in a variable called

total and then we're going to return

that total so let's go ahead and run

this function and we should still get

back 120. perfect very good let's change

the price of this 300 let's try it again

you can see that our our tip is 360

dollars now okay and it's working

perfectly now i do have to show you the

modern way of writing a function because

you're gonna start seeing that in a lot

of different places with javascript and

so this is the es6 way and this is these

are called arrow functions

so

um and also the variables let's let's uh

change them okay so let's go ahead and

do these variables in a way you know we

you we're using the var let cons so i

know that we didn't use it for a couple

of these other things but that's again

just so you can start understanding how

all of this stuff works in an easy way

but we're going to do const tip

percentage all right we'll do const tip

amount you could do cons or let either

should be fine okay then we're gonna do

const total three variables that we're

declaring okay so constant let and you

should you should be fine either way

remember if you do something const that

means you're not changing that variable

later and if you do

let that that's basically saying hey i

know i'm making this variable that i

know i'm going to change at a later

point i'm going to change its definition

there we go let's run this function

again and let's just make sure that it

works all right so now with arrow

functions how they work is they kind of

look like this okay so

um i'll make we'll we'll make this

function sum but we'll do it with an

arrow function okay so let's do some i'm

going to say const i'm going to say some

arrow is equal to

like that

so it's equal to and then you put in the

arguments all right so this is think of

this like a variable and then you put

the arguments here so here i'm going to

say a comma b and then this arrow here

so which is equal and greater than sign

open close squigglies and then inside of

there i'm just going to say return a

plus b so that's how you can write an

arrow function

and basically write the same thing but

an error function now here's the cool

part about the error function okay

because right now you're probably like

wait what's the benefit of this why am i

writing this uh when i can clearly write

it this way and this looks like easier

to kind of see and understand because it

says function error functions can look

really nice so here's what i mean by

that they have a superpower called

implicit returns where if you remove

these squigglies you don't even have to

write the keyword return it will

automatically return

that and so that

sum function that you wrote can

essentially be on the same line that's

some function that you wrote so it's so

nice and easy because your entire

function just gets written out like this

so you know it'll be like right i have a

function called sum it takes in two

arguments a and b and it returns their

sum okay so this is an example of an

implicit return so arrow function

with implicit return okay that's an

example of that and again i'll just call

this function some arrow so it's clear

for you

and then this is

arrow function with explicit return okay

let's put it here important for implicit

return remove

squigglies

okay so squigglies are these these curly

braces or i can say curly braces all

right there we go

so that's important to do if you want to

have implicit return where you don't

want to say that return so let's try

this some arrow function that we created

and see if it works we'll do console.log

and i'll say sum arrow and we'll give it

10 comma 40 50. and we should get back a

60. let's see if we get that back it

says it's been declared because i'm

defining it twice and remember i called

it const so if i'm calling it a const

here it's not going to let me redefine

this function later with the same

variable so i'll just call it some arrow

2 and call the function some arrow 2

here and we'll hit save command s or

just hit run and boom you see the sum of

these two numbers is indeed 60. so the

sum function is working so it's a really

nice way of creating your function so

for bonus points and for being fancy i

want you to always try to use the arrow

function because that's the modern way

of doing javascript and you'll see that

in majority of the code basis so i'd

rather you just get in the habit of

doing that now to wrap this exercise up

i'm going to leave you off with an

exercise okay to wrap up really the sum

functions and i want you to practice

with functions now here's what i'm going

to have you do so in files on the left

hand side okay i want you to go inside

of functions and go inside of something

called sum and then there's going to be

an exercise folder in here and a

solution folder so don't go into the

solution for this exercise yet make sure

to go into the exercise if you're

stuck and you can't make progress and

you can't really you're stuck then and

only then go in solution but don't go in

there as the first thing and in this

exercise i'll go and go to script.js

okay

in here

you will see that you have these

exercises like make a function called

add which is the same as sum so you

should have no problem making this

function make a function called subtract

make a function that divides two numbers

and make a function that multiplies two

numbers okay so all of these should take

in two arguments sub add

div and mul

they should do what they say here and so

we have some notes for you and what you

got to do so the to-do's are written out

for you here and this is the normal way

of doing it and for bonus points if you

want to be fancy use the es6 syntax for

error functions to maybe even convert

these into error functions if you want

to be a real boss and then at the bottom

make sure you also console log all of

these so

meaning you print out the result of all

of these okay or do some kind of call

now where you're going to have

difficulty is running this file so

you're going to be like how do i run

this file let me show you okay so over

here we have something for you can

exercises and if you want to see this in

full screen you can always hit this

button open in a new tab that'll open

this entire thing in a new tab that way

you can like guaranteed see it right

just in case some certain things are

hidden and what's cool about repple is

your code is already deployed on the

internet meaning like this is not just

on your local computer you could run

this anywhere like you could send this

link to your buddy and they could just

run this

at their place right like because it's

online this is online so they can run it

and like look at your code and so if you

made something you could be really proud

of it and show it to them so we have

this project solutions folder right so

this is where the solutions will be but

for functions here's the sum right so

you click the sum now if you do

console.log

hello from the sum file

okay or some exercise or whatever let's

just say that here and i'll hit save

if you click sum

it will say hello from the sum exercise

so meaning anything you console log here

will show up just make sure if you want

to run this file again you're going to

have to click

this sum link over here and that will

run your exercise okay

and also another thing i want to show

you is this is just html css javascript

so what's nice about this is you could

just download this folder as zip okay

and let's go ahead and open it

so i'm going to go ahead and open this

and go inside of here and you could

click this index.html and just run it

and it will run on your computer locally

so just so you understand that this is

real world right just because we're

doing it on online website doesn't mean

you can't use it in real life you could

just download that folder and run it and

now it's on your local computer so

that's just to kind of show you that all

your options and everything that you

need is available at your disposal all

right so but we're just coding here for

the sake of simplicity and replica just

makes everything really really easy okay

so that's it go ahead now and do this

exercise and once you return from doing

this exercise we're going to move on to

starting to talk about different types

of data data types like arrays objects

things of that nature okay so good luck

have fun

and go and crush this and i'll see you

in a minute

all right so now let's jump in and start

talking about arrays and right before we

do that let's go ahead and comment out

every single line

that is still running so line 108 for me

i'm going to comment out and i'm also

going to comment out line 121 and so

when i hit run nothing should be coming

out to my console perfect my console is

looking crispy clean that's exactly what

we want

so

let's go ahead and start working on

arrays i'm going to go here i'm going to

say arrays

okay

and why do you need a raise well what if

you want to hold multiple different

things how are you going to do that so

if you have groceries

right in a variable you could only have

one grocery like a fruit but arrays

allow you to have multiple things so for

example i could have an array that has a

banana

it also has

apple

okay i can also have orange

okay

we can also have a pair

all right i could have groceries like

this and you could write the words too

so this is just a string and i decided

to put an emoji in it but you could

decide to put like the actual word pair

here if you want but i just think that

this looks

prettier right so that's why i'm having

it like this

now if i'm doing

all right and remember to just put a

const here okay so we're just going to

say const groceries and here we go we

have all of these you know we got a

banana we got an apple we got all this

awesome stuff in our groceries right now

let's console log groceries

okay

and let's hit save and let's see what

happens i'm going to move this here and

boom you can actually see that it

printed out all of the groceries okay

now how do i get just a banana if we if

i want right so if you click it it shows

you the zeroth element is a banana the

first is the

apple the second is orange and the third

is pear okay and remember everything in

coding when you start counting it

usually starts from zero

so it goes zero one two three

and the length of this is four okay

because there are four items in here

four grocery items now

how can we get just a banana if we want

just a banana how do we do that well

here's what we do we go console.log

groceries we put this bracket and we do

zero okay and let me hit save and let's

see boom we just got the banana okay

well what if i want an apple what do i

do can you take a guess i'll give you

five seconds see if you could write that

yourself five

four

three

two one

all right let's do it so you would have

to put in a one here okay so boom let's

do that let's do a one let's hit save

and boom you see we got an apple now how

would i get not the orange but the pair

so how would i get the pair make sure to

count correctly zero one two three right

how would i get the pair what do i need

to put in these brackets to get that

pair i'll give you five seconds here

five four

three two one all right let's do it

we would do three

okay

and you can see that we got the pair

okay

so again this is zero this is one this

is two and this is three okay if we want

to get the orange we would simply

pop in a two here okay let's give that a

try make sure you're coding along with

me and you're just exercising with me

okay make sure you're not just passively

watching this make sure you're coding

along with me every single step of the

way that's how you're going to get

better so this is called indexing okay

this is like you grab one of the indexes

okay so here i'm getting grabbing

grab the second

or like the third index in this case

okay um

or second index okay grab the second

index

that's basically what we're doing here

or grab the second item if you want to

say it in a more human language but in

programming this is a zeroth index this

is the first second third so if you ever

hear like hey it's in the first index or

the third index that just means where

its position is in an array okay and

arrays are really really cool and i'll

show you a lot more about them soon all

right so take a look at that right at

the bottom you can see

that and let me remove let me cons let

me comment out this line here okay and

let's run it again

and i'll move this up over here it's

easier to see but take a look at this

right over here

before we add the cookie and we console

log this out notice that there's no

cookie in here right but after we do the

push and we console log it out watch

what happens

now we have a cookie that's added that

wasn't there before so that's what push

does push adds things on to the end of

the

array okay so try adding something else

try adding a chocolate try adding

uh a blueberry try adding something and

see what happens and see if you could do

it yourself okay so add something more

here let's you give this a try so i'll

give you five seconds five four

three two one all right now let's try

adding something together so i'm gonna

say groceries dot push okay and we're

gonna say

i'm gonna do let's do blueberries

okay

and then i'll console.log here paste it

here hit save and run

and check it out we got

we got one

the regular

uh groceries array

then we got this with the cookie this

time okay and then we push the blueberry

and you can see there's a blueberry at

the end there

so that's how the push method works okay

great so let's um

comment out

all of these for now all the console

logs so if you run your code you should

see basically nothing okay it should be

empty just like this

perfect now what we want to do is we

want to

try grabbing like what if i only wanted

the banana

okay what if i only wanted the banana

and the apple

okay those are the only two things or

the orange and the pear and that's all i

wanted okay

well for this there is a method

called

slice

okay so we're going to do that so we're

going to says groceries

and i'm going to say slice and i'm going

to say 0 to 2 and let's see what happens

okay and let's make sure we do console

wrap this in console.log because

otherwise it won't show it to the screen

let's hit command enter or ctrl enter

and boom look at that we're getting

banana and apple so it's starting from

zero including zero okay so basically

what we're saying is start from zero

inclusive

and

up to

two okay but but not including two

okay so basically it's giving you the

the index this is giving you is either

zero or one that's the index it's giving

you so it's either giving you this

or that okay so if you want to get the

first two elements you can do it like

this okay up to two if you want to get

three elements you do this

okay so if i run this it's gonna give me

three elements if i do four and run it

watch what happens it's gonna give me

pretty much all of the elements right if

i hit five it's gonna give me the cookie

as well that that we added and if i do

six it's going to give me all the way up

until the blueberries that we've added

because we still have the push grocer's

not pushed there

boom so you can see the blueberries so

when i do zero to six it's gonna go from

zero to actually the fifth index and

give me

up to that point cool all right now

question for you what if i wanted not

from zero but if i want it from

right here the pair

until the blueberry so what if i wanted

this part of

the array can you splice that and get

that out of the array for me please take

a few seconds take five seconds

five four three two one and let's work

on it together okay so i'm going to try

and i'm going to do okay let's do up to

six

one two three four five

okay like that

this is just an example

so let's do console.log

and we're going to do groceries dot

slice and i'm going to say

so let's actually count together okay so

we have

0

1 thank you baby appreciate it

2

3 okay so basically we're going to say

give us from 3

2

4

5

and 6

but it's going to go up until five

okay

perfect so let's go ahead and do that so

i'm gonna go

zero

sorry three two six and let's see if

this gives us what we want so i'm going

to hit run and boom it gives us from a

pear

to a blueberry let's try another example

okay keep doing this with me don't get

lazy on this keep trying this with me

while i take a sip of my water that

my girlfriend brought me but try getting

me apple to a pair okay try getting me

this

right over here okay take a second

um and see if you can get me those three

right here okay so take about five

seconds

all right

five

four or take take a little bit longer

while i sip this water

okay

so let's give that a try

i'm gonna go ahead and do i'm gonna

change this to a

one because one will get me the apple

and it'll be zero

one two three and four one ahead of the

one that we need okay and let's go four

let's hit run

and i get apple to appear exactly like i

wanted right it was that

that's what i wanted

and that's what we got

perfect

very very good very good okay let's keep

making progress now all right so now

before we graduate from uh slice

and if you notice that i changed my

shirt i just had to do an interview

because they were because my girlfriend

is a wow superhero she's candy crush

and um they're doing a documentary on

her so i had to go do the interview and

i had to change my shirt because i

wanted something black and my previous

shirt was yellow and nice and poppy and

so i don't know why i'm telling you that

but

i thought you should know let's go back

all right

um so here

groceries slice

so this is good but before we graduate

i'm going to teach you about two

different array methods okay so there's

a couple of array methods that i want

you to know so

we went over slice we went over push

i want you to learn index of and i want

you to learn

uh length okay

this is probably the most like one of

the most common ones length uh so let's

just go through it together real quick

so now i'm going to say console.log and

we'll do groceries okay

and i'm gonna do index of and what index

of does it it will give me the index of

these fruits okay

so let me just comment out these i

comment these uh slices out here so i'm

going to hit run

let's just do

let's just run that one so we can see

all of our

groceries or fruits

perfect and so index of what it's going

to do is if i ask for the index of

orange it's going to literally give me

what the index of that is so can you

tell me what the index of the orange is

for example banana is zero apple is one

so orange is

you guessed it too

so let's see what it says

all right so let's uncomment these lines

and let's go here and we're going to pop

in orange here

okay we're going to say hey what's the

index of this orange let's run it

and i just gave back 2.

all right let's ask it about the pair

and let's run it and it gave back three

because this is three okay so that's

what index of does helpful to kind of

know you won't be using it too often i

mean honestly when i'm coding majority

of the times i don't use it but i just

thought since this is the array section

i cover these methods because they're

going to be helpful for you all right

i'll comment this out for now so index

of and then the other method you need to

know is dot length okay so that one is

going to be important so let's go ahead

and do console.log

groceries and can you guess what length

is going to tell you

dot length

length starts from 1

and so it will take the overall length

of this so however many items are in

here

is going to give you that back so let's

count one two three four five

six

so length is going to give you back

six

all right let's give it a try and let's

run it boom there we go see that six

right there

that's it that's that's what uh that's

what length does

okay perfect so now we can basically say

you've graduated from arrays yay good

job there's a bunch more to it but this

is just over simplified you know what

arrays can do you'll learn a lot more

about arrays a lot better once we get to

the loops because there's a lot of cool

things you could do with arrays they're

like my favorite thing in coding i think

arrays are literally my favorite thing

and next up we're gonna start learning

about objects okay so let's go ahead and

start learning about them now all right

now let's talk about objects so here's

the first thing we're gonna do we're

gonna comment out line 144 and 135 so

there's nothing being printed okay let's

go ahead and hit run and look at that we

have nothing coming out to the console

log that's perfect all right now let's

go ahead and let's talk about objects

objects are really really important and

they're really awesome so in just one

second we're gonna work on right when i

snap my fingers we're gonna work on a

new object all right this is the object

we're gonna be working on so as you can

see here we have mr leonardo dicaprio he

is our he's our object in this case and

he has a couple of properties so his

properties are he has a name so if you

do person.name you know that should we

need to set that to leonardo

and then his shirt here will be white

okay because if you can actually see his

shirt is

white back there so we need to create an

object that actually represents that so

let's go ahead and do that now so i'm

going to put him

over here kind of in the corner so you

can see him now let's create an object

to represent this so we're going to say

cons person and object is created by

doing these squigglies okay so these

squigglies represent an object so so far

right here we have created essentially

an

empty object

now what we're going to do is we're

going to add some properties

to that

person object okay so we're going to add

a name so the name of this person in

this case will be leonardo and shirt

will be white

this is an object if i format this you

see this is how an object looks if you

want to make it look a little bit like

prettier and kind of how you know pros

write prose would probably make it look

like that okay kind of how it looks like

here so open squiggly close quickly it

doesn't matter if you have it on the

same line or you don't okay so it

doesn't really matter which way you have

it

both ways will work all right now this

here pretty fairly represents what we

have over here you have a person object

the name is leonardo shirt is white now

let's go ahead and console.log and

access some of the properties of this

object that we created so we're going to

do person.name and when i console this

you're gonna see that the person name

and i'm gonna move this up here okay

when i when i run this you can see that

the person name is indeed leonardo kind

of just like what we wanted right and

the start and can you guess what person

that shirt is going to give me when i

type that in and when i hit run take a

guess

exactly you're going to get white okay

just like we had expected here because

those are the properties and that's how

you access them so that's how objects

work so first let's learn different ways

of accessing this object okay dot

notation

versus bracket notation these both of

these you should know okay so how do you

access objects so you're right now

you're using a dot notation now here's

an example of a bracket notation let's

do console.log and we're going to say

person and we're going to do name like

this

and let's run it and boom you also get

leonardo right over here

well give it a try try doing the shirt

but with the bracket notation try

accessing it i'll give you five seconds

five four three two one all right let's

see if you got it so i just triple

clicked to copy and then i did command c

to copy and then i went down and command

v to paste you could do ctrl c or ctrl v

to copy and paste and then double click

the name inside here change that to

shirt hit command s or ctrl s if you're

on windows to save and automatically run

apparently it's not automatically

running so let's run click the button

here or command enter and boom you can

see that the shirt is coming out white

right so we got different ways access an

object that's really good now there are

different ways to assign

things to an object as well so for

example i could give him a phone number

okay so i could actually do person.phone

so notice we don't actually have phone

in here and i could do phone

and we could give him a number

like that okay

person not phone and then we're going to

go ahead and do console.log

and we'll say person. let's go ahead and

try it let's see what happens and boom

you can see that

we actually get that phone number right

there but also you can actually console

log the entire person as well so you can

see what that looks like so let's go

console log person let's go ahead let's

hit run

and you can see you can see this object

right over here

name shirt phone so now this object has

all of the things and it didn't have

that before so it's kind of like how in

arrays we were almost doing like push

it's kind of like that but like it's

just you're creating a new key on the

fly and giving it a property another way

you could actually create that property

is by putting this in bracket notations

as well because you could go like this

bracket notation and say hey person

phone is actually equal to this hit run

and watch what happens boom you got the

same thing and that also works so both

work okay the reason why we're putting

the phone number in quotes by the way as

in we're making it a string is because

if you didn't do that it would try to

subtract it will do 1 minus 2 2 2 minus

3 3 3 minus 4 4 4 and evaluate to a

big negative number

that's not what we want right so put

that in quotes because we want the exact

phone number and phone numbers or

strings all right so now let's say you

want to create another person okay so

i'll give you an exercise for you to do

and let's go ahead and do this

right now so i'm going to give you a

different person with different name and

different shirt and i'm going to need

you to create an object

a person object that represents that

okay so you can call that object person2

alright so let's go ahead and do that

here you're going to call this object

person2

all right so now instead of leonardo

dicaprio you're going to get somebody

better yours truly

and you have the object right over here

okay so this is the object that you have

and these are the properties that this

object have okay so try to see if you

can make this object by yourself either

pause my video

or take a couple of seconds right now to

do this but i'm gonna start doing this

in five four three two one okay let's do

it so i'm going to basically there's a

cons person two

and i'm going to say name is causey

right and make sure to put a comma so

after every property right so let's go

through an object so we have squiggly

bass squigglies in the start and closing

okay instead of brackets

object uh arrays have brackets

and then you have a key and a value all

right so objects are key value pairs

all right so you have a key here and a

value here a key here and a value here

okay

so

a key you can also sometimes call it a

property okay so here the key is name

and the key is shirt okay and name and

shirt is also the property so you could

say kind of both ways

so you put in the key right person name

and you get back the value which is

actually the name

right you do the same thing here with

the phone

so you take your object

you put in the key

right and then that key unlocks and we

set this value for that key

again we do person.phone so we did the

object and the key and then the key

gives us the value

all right kind of think of it like

opening a lock all right so name here so

this is the first key value the second

key value we're gonna set is shirt

is black

okay and uh that's it that's the way you

represent this object right so if we do

console log person2

and run it

boom you can actually see that it's

showing you quasi

uh and shirt is black okay that's super

cool and uh if i change this to you know

what if i want quasi's name what if i

only want the name can you try that for

me if i only want the name

boom hopefully you got this correct okay

let's run it and now we're getting the

name well what if i want the shirt as

well

same idea right if i run this we're

gonna also now get the shirt so shirt

color

and we got it as black let's turn this

into a function that then

says hi my name is kazee and my shirt is

black okay so let's go ahead and create

a function okay so remember how we

create functions right there are

different ways you could do function

or you could do the

fancy way like this

we'll call this function introducer

because it introduces you to other

people okay

and this is going to take in

let's say we can give it a

shirt

and uh it will also take in a name so

let's go name and shirt okay

and if we want to turn this whole thing

into oh sorry whoops and we're going to

do

if you want to do error functions this

is how we're going to do them okay so

we're going to go ahead and say

name comma shirt and we're going to do

arrows like this i'm going to go here

all right now the final sentence that

we're going to return

right is going to basically be remember

template literals all right so let's use

the template literals again and we're

gonna say

hi my

name is name

okay and we're just gonna say name like

this for now

my name is name and the color of my

shirt is whatever the color of your

shirt is okay so in this case it should

be like black

so here let's say if we had it

hard-coded it would be like this but we

don't want it hardco um we don't want it

hard-coded right so we're gonna do here

is name we're going to make it dynamic

we're going to send name

and remember and see if you can make

this shirt dynamic as well boom we're

going to say sure

and we're going to save this into a

variable called intro the const intro is

equal to that

but we're going to make an object first

so just so you can keep practicing an

object okay so we're basically going to

say we're going to create a cons person

object and this object is going to have

a key name and the value of that key is

also going to be named because that's

what we're passing it i'm just going to

say name right here and it's also going

to have a shirt and that's just going to

be the shirt that we pass it okay so

these are

values that we're giving it these are

the actual keys that are hard coded okay

so these will stay the same these will

be exactly name and exactly shirt and

this part will be dynamic these are the

values that we give it and so then we're

gonna in order to get this person's name

remember what we have to do right it's

person dot

name perfect and now how are we gonna

get this shirt we're gonna do person dot

what

person dot

shirt perfect good job if you kept up

with that okay so we're creating an

object right here and we're creating the

intro and now we're just gonna say

return the intro all right

that's our function and let's give it a

try so let's go console.log let's call

our function introducer and let's give

it a name qazi and let's give it a shirt

color and we'll say black and let's run

this and look at that right we're

getting hi my name is kazi and the color

of my shirt is black beautiful so we're

using template little i mean this is

advanced this is awesome if you're doing

this good job for doing this this is

using this is a

es6 error function right this function

has

two arguments

and you created an object in here

and then you're using template literals

so there are a lot of concepts in here

that you're doing so great job on

following along and doing this with me

even if you didn't get it it's good that

you're you know you just followed along

and like did it and hopefully you got it

working on your computer like that's

what's really important so here i have

this and if i if i show you right hi my

name is kazi and the color of my shirt

is black now let's go ahead and comment

out all the other stuff that we had here

right so i'm going to comment this out

um you can leave this or comment it out

i'll just comment it out

you can comment out pretty much

all of this

okay and i'll comment out this person

right here too and we'll just hit run

and it should just say hi my name is

kazi and the color of my shirt is black

okay so

the only console log that should be

happening is the one coming from this

function this function is super cool

because this function is like creating

an object and then doing the template

literals accessing data from that object

very nice okay this is a very very nice

well-written function so good job if you

got here so far now try

see if you can now do this call the same

function but see if you can call it on

leonardo and with the shirt being white

so give that a try i'll give you five

seconds five four three two one all

right let's do it together so i'm gonna

say console.log we're gonna say

introducer

and we're gonna see leonardo here

right and the shirt color is gonna be

white

these arguments have to match right so

this matches that

and then this matches that okay so these

arguments the order here matters okay

and uh let's run this and let's see if

it does the leonardo one as well and it

does hi my name is leonardo and the

color of my shirt is shirt okay so we

probably gotta say white here hi my name

is leonardo and the color of my shirt is

white

beautiful this is doing exactly what we

want we're going to go ahead and comment

this out

and so far you're doing absolutely

fantastic

all right now let's take this even a

step further let's say that we want to

have this person but we also want to

calculate and have their net worth okay

so i'm going to go ahead and refresh

this page and let's just uncomment the

quasi in black here perfect my name is

kazi and the color my shirt is black

blah blah perfect we want to say this

person has certain assets okay so assets

they have is like let's say a hundred

thousand dollars all right and the debt

they have is fifty thousand dollars so

if you wanted to calculate the net worth

is really easy just assets minus debt or

assets minus you know you could say

let's say liability

all right

so

it's how much basically money do you

have and then how much debt do you have

it's very simple for an average person

if you want to calculate your net worth

you could do that right now like it's

very easy you could have a negative net

worth or a zero net worth and if you

have a positive net worth that's

incredible so here you would have a net

worth of fifty thousand right hundred

thousand minus fifty thousand we could

do that right and so we could say and my

net worth is and i could do this and i

could basically say a person.assets

minus person dot liability like

abilities

and paste that there okay

so let's run this and let's see what we

get hi my name is kazi and the color of

my shirt is black and my net worth is

fifty thousand dollars we could put a

dollar sign here right and we could say

we could say we you you don't need to

say usd but you could if you want and

says my name is blah blah my net worth

is 50 000 usd so this dollar sign is uh

pretty much to actually put a dollar

sign and then the next dollar sign and

squigglies are to basically say hey i'm

writing javascript so let's make this

even nicer i'm going to teach you how to

create methods

inside of an object okay and anytime

you've seen dot met something that's

usually a method okay when you're

calling it so like math.floor remember

when you saw math.floor

this is a method if you didn't have this

math part here and it was just like this

this would be a function and if this

open closed parenthesis weren't here

this would be a property so i know it

can be confusing but here's a great

example all right you have an object

right here properties are just with dot

to car.name card.model those are all

properties right but

methods are car.start with the open

close print card.drive open close print

car.break open close paren so methods

look like this all right so just kind of

take a mental screenshot of this for now

all right so here's what we're going to

do here's a really cool thing in kind of

advanced things you could do with

objects so i can actually create a net

worth field and what this will do is

what i essentially want to do is want to

say hey assets minus liabilities but if

i do this i'm going to run into a

problem okay so let's try that so let's

remove all of this and let's paste just

netperson.net worth and let's see what

happens if we run this and it says

assets that's not defined and and you're

probably thinking wait assets is defined

right here so why isn't it just using

assets this is that's not how it works

so in when you're defining an object

because all of this is happening at the

same exact time this isn't like created

yet and so it doesn't know so what you

want to be able to do is you want to be

able to say person dot assets but it

also won't really know that so here's a

hack here's a way that we do this okay

so we're going to create a function and

yes you can actually store functions

inside of objects which is kind of crazy

open close paren all right we're just

going to do this this is going to be

your net worth function and what it's

going to do is it's going to return and

we're going to say this dot assets minus

this dot liabilities this thing is kind

of weird but what this is referring to

is this specific person object that

you've created so it's literally like

imagine plugging in person.assets and

person.liabilities okay but you're going

to use this this whole thing here is

going to become 100 000. and this entire

thing is going to evaluate to 50 000 and

then this thing is going to evaluate to

50 000 like this and then once you

return this it's going to pop up in your

console so let's go back boom this

assets sold liabilities and net worth is

a method so even though we've defined as

a function it is a method and i'll show

you why because now in order to call it

if you do person.net worth watch what's

gonna happen it's not gonna work let's

run it and we just got

hi my name is kazi and the color of my

shirt is black and my net worth is

function return assets so just like just

like spit out this entire function

that's not what we want we want the

actual result so we need to call this

method and this is how you call it okay

boom you call it just like a function

but because it has a dot here it's

called a method so the person has a net

worth method

now let's run it and watch what happens

boom

right my name is causing the color of my

shirt is black and my net worth is 50

000

and now to make this code even more

dynamic assets and liabilities should be

passed by the user okay so that could be

like another thing that that might be

nice right now it's hard coded but

that's okay we can just kind of leave it

as is just to kind of show you that you

could do some more advanced stuff with

objects all right so let's run this okay

and if you change the name it'll also

work change the assets liabilities

you'll get different numbers all right

so if you got this far great job uh

we're gonna hit run on this to just make

sure we we're gucci but if you got this

far

you're almost an object

master so good job okay

you probably don't know like everything

there is to know about objects okay but

like you know more than 98 of the

population so you should be proud of

yourself give yourself a pat on the back

right about now go ahead and do that for

me and and you're beautiful and you

matter

and i'm happy that you're here so thank

you warms my heart all right with that

said let's continue all right now we're

going to be doing my favorite part

without this part you pretty much don't

have programming so this concept that

you're going to learn right now is going

to put everything together and it's

going to make everything do you do so

useful and it's not just going to be

like why can't i just do this in excel

why can't i just blah blah this is the

most important thing let's get into it

and this is called for loops loops

are the heart blood and soul of computer

programming and i'm just so excited that

you get to learn it right here with me

so if you're enjoying this so far smash

that like button so this video goes out

to more people helps more people become

developer and it's free so do it right

now and let's keep on rocking and

rolling so we're going to use loops okay

and let's go ahead and grab our array

that we made earlier with groceries okay

so i'm gonna just go ahead and copy it

so let's go boom grab this

const groceries okay i've defined it

above so what i'm gonna do is i'm just

gonna comment all of this out because if

i've defined a const above i can't

redefine it below so i'm gonna make sure

it's commented out and then i'm gonna

come down here and i'm gonna pay his

groceries okay and let's call it fruits

cause let's be let's be real that's what

it is right so now i have fruits well

what i wanna do is i wanna like print

out every single one of them so how do i

do that well here's a way you could do

it right console log we'll do fruits of

zero and then we'll just keep repeating

that

pattern right one two

three and then what will happen

essentially is this will get you this

one one will get you that one two will

get you that one

three will get you that one right

hopefully that makes sense so far so

let's go ahead and run this

and you get all four of these right

that's perfect but what if there were

like many many more like so if i just

copy this and i just keep let's say i

copy this and i just keep pasting it

right well that's a lot how are you

going to like print out all of those

it's going to be a lot of work are you

really going to do this right and then

what if they're more than that because

netflix has a what you know let's go to

netflix right now so here's an example

of an array this right here is an array

all right that's how you see these five

profiles one two three four five that's

an array when i go inside of this

everything that's showing up here is an

array so here's an array of new releases

here's the array of true crime

documentaries here's an array of

trending now these are just arrays all

right so if i have this many movies i

can't just like do them manually i need

something that can automatically find

out how many movies there are and then

like print them out okay or show them so

that's an example of you know why you

need to learn something called

looping okay or for loops so let's go

ahead and do that now all right so

here's how we're going to write our for

loop we're going to say 4 and we're

going to say let i equal 0 and then put

a semicolon and we're going to say while

i is less than and i know this is going

to look super weird but just trust me

hang in there with me okay fruit's not

length and we're going to do i plus plus

like everything here you're going to be

like what the hell am i looking at and

we're going to break it down in a second

but first let's just run it and see if

we can get it to do what we want it to

do and i'm going to say fruits and get

me the

get me the iath fruit okay let's run it

and let's actually console log this

console log and let's comment out all of

these four lines right here okay let's

run this and you see it it printed out

every single fruit that we had right all

of these fruits every single one of them

and how i can prove that too that i

print every single one out what we could

do is like put i there and then do this

and i'll actually even count it for you

so this is zeroth one first second third

fourth fifth sixth

all the way up to nineteenth okay so

there's like

20 total items in this array so this

loop is doing that this for loop right

here it's looping through automatically

auto magically figuring this out but

let's break it down what is happening

really so we're saying this loop we want

an index why do we want an index well

imagine if i instead of i imagine i put

a zero here well it's gonna run but it's

just gonna keep on getting the banana

every single time but that's not what we

want so what needs to happen is we're

essentially trying to mimic this process

we want fruits to be zero the first time

fruits to be one the next time fruits to

be two the third time fruits to be uh

this the fourth time

right so this is what what we're doing

here so the start i is set to zero and

all a loop does is it just repeats the

same line of code again and again and

again and again and again fruits.length

all i'm saying here is hey run the same

amount of times there are items in this

array so meaning in other words we want

you to run 20 times so while i is less

than 20. so run 20 times that's what

this means right here okay and as soon

as it runs 20 times and it tries to run

the 21st time it just stops and it

doesn't run again and i plus plus means

every single time you're done running

just increment i by one so first time it

runs i is zero okay so we put a zero

here and there's a zero here and you

will get your first item which is gonna

be

this item right here then it's going to

run again and here's what's going to

happen i is going to become 1 next time

the loop is going to run let's start

from the scratch right so it goes 0

less than 20 is that true or false i'm

asking you

that's true 0 is less than 20. so then

this line of this line of code here runs

and it prints this out pops it right

there perfect then once we're done

running it increments i by one so now i

is one is 1 less than 20 yes or no yes

it is okay 1 is less than 20. so then it

runs but next time because there is an i

here fruits becomes 1 because it's

dynamic like that so then it gets you

this guy right over here then it runs

again and it does the same thing too so

it goes to 2 less than 20 goes yes pops

in a 2 gets you the orange because

that's in position 2 right here then it

increments i by one i becomes three is

three less than twenty is that true or

false yes it's true and it prints out

fruit of three so then you get this pair

then it goes again and increments this

by one so this becomes what

4 good

and then it prints it out

all right

i'm going to ask you this time what is i

now if you guess 5 good job because

after running this we increment i by 1

so i is 5 now it's 5 less than 20

okay this is 5 and this is 20 and this

thing then becomes true and then once

this becomes true this part of the loop

runs all right so is this less than 20

yes it is then this becomes 5 and then

this prints this out so on and so forth

so this is why we just leave a i here

okay so that's how loops work they're

really awesome

real really nice and uh they make our

life easy now

now now now now here's something

exciting i'm going to show you

you pretty much never

ever

ever have to use this ugly looking loop

ever again this is really the only time

you're going to be confused thanks to

the new javascript

ways of doing it and i'll show you them

and after that pretty much never write

this ugly loop i never write it i don't

deal with these weird indexes and

honestly i even forgot how to write this

ugly looking loop should be eradicated

from most of what you're doing in your

day-to-day i'll show you a much easier

way of writing all right so now let's go

ahead and comment out this entire for

loop that we wrote and instead what

we're going to write is we're going to

say 4 and watch this we're gonna set

kant's fruit of fruits okay and we're

just gonna say console log fruit and

watch what happens i'm gonna

run this and it does the exact same

thing and you do not have to worry about

indices at all so this is so nice so

here's how this is working fruits this

variable here fruits is important this

is this right here this is the fruits

array this variable here right here

fruit i'm making it up on the fly i

could call it whatever i want i can call

it john but i just got to make sure that

i put john here and john here and boom

we run it the only point of this

variable right here is fruits in this

case will be the name of you know it

refers to this which is this entire

array right here this entire array right

here okay that's what fruit says but

fruit when you're looping the first time

it's this banana and when you're looping

the second time it's this apple and when

you loop again is this orange and when

you loop again it's this so you don't

have to even worry about indices this is

the fruit and then in the next loop this

is the fruit and then in the next loop

right this is the fruit this is the

first loop and the second loop and the

third loop the fourth loop and then you

just print that out so like i don't know

if you if you look at these two side by

side right this looks like an eyesore

and hurts your eyes and you will get eye

aids by looking at this and then you

have this one

just

this is beautiful this is pure gold i

mean this is how this has meant to be

right this is how it should things

should look and feel this is very

pythonic python you write loops like

this this is really really nice so we

like this one much more than this one

okay so stick with this one and then

i'll show you a couple of other things

you can do as well all right so now

let's do something else with arrays okay

so we're going to say const numbers and

we're going to create a array and it's

going to keep our number so one two

three four five six

well

what if we want to um so we'll do a

couple of things right i'll show you how

to sum up

all numbers in an array because that

will be something helpful for you and

important for you to learn but we want

to do now try this write both of these

loops for this numbers and print out

every single number how we're printing

out our fruits okay and comment out

everything related to the fruit okay so

hit run and you should see empty and

loop through so then all the numbers get

printed out from one through six try

that i'll give you five seconds five

four three two one

all right let's write it together so

we're gonna say 4 let i equal 0 okay i

is less than

numbers dot length all right you kind of

get used to writing this for loop once

you write it a couple of times but again

we're not even going to be using this

one that much anymore so get ready to

say goodbye to this one all right let's

run this and let's see if it works boom

one two three four five six so this one

worked exactly how we expected it to

fantastic okay let's go ahead and let's

comment this out let's comment this out

and now we're going to say we're going

to write the other loop so we're going

to say 4 const number of numbers and

we're simply going to just say console

log number and let's hit run and boom

one two three four five six don't make

the mistake of printing out numbers

because what you're doing here you're

just going to print out the array

five five times you don't want to do

that let's just say number boom there we

go so that should that printed out

everything hopefully you got this

correct and if you didn't it's okay

don't stress we'll have some additional

exercises here in our files for you to

do

with arrays okay because arrays are very

very important so we got this six now

what if we wanted to double every single

number right over okay so let's go ahead

and try that how can we do that how can

we print out 2 for this 4 for this 6 for

this 8 for this 10 for this and 12 for

this okay how do we do that so what we

want to do here is you actually you

could actually do it right here give

that a try see if you could figure that

out you have enough tools to be able to

figure this one out right now and i will

tell you this you don't even have to

write an additional line of code that's

the hint i'll give you you can fit that

in on line 221 and basically have the

answer to this problem so either take

five seconds to do it or pause the video

i'll give you five seconds now five four

three two one

all right so we're gonna go number times

2. that's it

let's run and now we get 2 4 6 8 10 12.

everything is doubled you guys that's

awesome but what if we wanted to do it

so that this numbers are right here is

doubled so or like we get a new array

that's like all of these numbers doubled

how could we do that double numbers how

could we double the numbers and

basically at the end get back an array

that says 2 4 6 8 10 12. how could we

put this in and get this out so let's

give that a try all right so here's what

we're gonna do we're gonna pretty much

have this same loop that we have here

but we're gonna need to create an array

that like stores that results right

we're going to say let result is equal

to and we'll just make it an array like

this all right so we're just going to

have this empty array it's going to be

empty at the start and the trick that

we're going to use is remember we did

push so again you have enough to figure

this out if you want to try but inside

of this for loop you're gonna push to

this results array double this amount so

see if you could figure that out and

then console.log result and get that by

yourself you have enough to figure out

it might be a little bit challenging

though right now i'll give you five

seconds you can pause the video five

four three two one and now we're gonna

solve it together so all we wanna do

here is i'm gonna do result dot push

number times two all right so i'm gonna

loop through and then push so then i'm

gonna have two then i'm gonna loop again

and number is going to be

two and we're gonna come down here

2 times 2 is going to become 4 right so

we're going to result that pushed off 4

that's going to add a 4 right here and

then we're just going to keep looping

through this array and just keep

doubling it every single time and then

pushing the double result in here in

that result array okay so let's remove

that

and then once that entire loop is done

so make sure to put the console log of

result outside of this for loop okay

because we don't want that repeating

again and again let's comment that line

out or we can actually just even delete

it here we don't need that anymore let's

try running and watch what happens boom

we have an array with 2 4 6 8 10 12. so

that array doubles all of the numbers

so this is an example of how you could

do something like this all right now

what we would want to do is turn it into

a function okay so we're going to

basically go

const

double okay we're going to call this

function double and uh this function is

gonna you can you could call it you

could either call it function or you

could use this arrow syntax to highlight

that this is a function right it's the

es6 function and what we're gonna do is

what this function does is takes in

numbers and we'll have the same loop so

we'll say const number of numbers

grab this result right here we're going

to paste that in so it's going to create

a temporary recall result it's going to

loop through the numbers that you gave

it it's going to keep pushing double of

that result into result array and then

at the end we're just going to return

result just like that all right and we

can get rid of all of this right here

and let's try running double so let's do

console.log we'll say double and let's

give an array to double so one two

three four five six and let's run this

and let's see what it outputs two four

six eight ten twelve that is perfect you

guys that's exactly right that's exactly

what we were looking for so that is

beautiful nice job if you got this far

question for you what if we wanted to

turn this function into the square

function meaning we square all these

numbers how could we do that so think

about that squaring means using

exponentiation instead of multiplication

okay so how could we turn this function

into something that squares numbers so

meaning 1 squared would be 1 2 squared

would be 4 3 squared would be 9 4

squared would be 16 5 square would be 25

6 squared would be 36 right so how do we

get that array back well it's simple

just put another asterisk right here hit

run and there you go it's all

perfectly squared so let's go back boom

i'm gonna just turn back into a double

all right so that's how easy that is now

imagine if the size of this array

changes 7 8 9 20 40 and watch right when

i run it boom it just works instantly

right this is the crazy part about like

when you write good code and i'm just

gonna like fill it up with crazy numbers

here right i'm gonna make this really

really big you're getting a big data

file in excel or something and watch it

just it just works on the whole thing

insane right and it says 177 more items

this is the beautiful thing about code

so when again when you go look at

netflix right so let's go let's go to

netflix again and let's take a look at

this this is an array and what we're

doing to that array every single time so

like we have some data in that array and

we style that data every single time we

loop through so we we write a for loop

and we loop through and we say take this

data the billion dollar code text the

image url that's how you're seeing the

image and turn it into this card and

then do that again with the next movie

so almost imagine that there's a loop

for right or const movie of movies and

what you do here and we close the

squiggly right there and we say you know

return

movie and let's call this function card

and let's just say this function card

turns it into this nice

neat card okay we don't let's say we

don't know the details of this function

but what this card function does is if

you give it a data of a movie like the

name of the movie and the image of the

movie it turns it into this nice little

card over here then you loop again and

then you do it again you loop again you

do it again you loop again you do it

again you loop again you do it again i

mean god damn i should be called

freaking senior loopy because that

there's a ton of loops there that's the

crazy part you guys this is real world

stuff okay it's not just like me telling

you random stuff it has a very real

application even though we're doing like

beginner exercises right now just so you

could get better at it because if you

don't know how arrays work then if i

give you something more complicated with

like cards and images in html and css

you're going to be so confused so you

have to learn these by themselves like a

martial art you got to learn the rear

naked choke by itself and you got to

learn the kimura by itself and then you

got to learn the positions and then you

learn these esoteric positions in jiu

jitsu and you're like what the heck is

the point of this and then one day you

just it to hit that triangle you like

rotate your hip you angle your leg the

right way you grab the neck the right

way you twist the right way you pop your

right leg and you pop the left leg and

you get that triangle just boom

everything and it all happens at once

and it's so smooth and it's beautiful

but when you're learning it you learn it

like step by step and same thing with

chess or anything else in life soccer so

we're just learning the components and

the pieces by themselves and then later

you'll be able to put them together with

more impressive stuff okay when we get

to the project portion all right now

let's keep having more fun with the

arrays because the more practice you get

with arrays and loops the better of a

programmer you're going to become

because honestly that's like 90

of what you're doing in programming

you're usually getting max a lot of data

and you're looping through it and you're

doing something to it okay that's like

super common and so let's just get a

bunch of different practices in all

right so

we're going to go ahead and make another

function and this function we're going

to make is going to be called letter

counter okay so let's go letter

counter you can also call it counter

whatever you want and

we're going to use it making an error

function

all right and basically what this

function is going to do

is it's going to take a look and see how

many

letters are in a given phrase okay so if

i gave it a phrase

let's say khan's phrase is equal to uh

hey can you

go to grocery

store

okay whatever

all right this will go through this

whole thing and it will basically just

just count how many letters there are

okay let's call it how many letters

and so you're just gonna go through and

this is gonna be a one there's gonna be

a two this is gonna be a three a four a

five for the empty space six seven eight

nine so you can do this you can count an

empty space as a letter that's totally

fine so think about how you're gonna

write a function like this right think

about what are you gonna need to do well

you're gonna need to loop through this

and the cool part is you can actually

loop through these types of phrases you

can loop through strings as well first

let's comment out um anything we kind of

have up here okay perfect and now in

here i'm going to go ahead and i'm going

to say let's let's write a loop okay i'm

going to say 4

letter in phrase and let's see if this

works and let's do console log and we'll

say letter okay and let's hit run and

let's see what happens okay it's running

okay so what we need to do in order to

make sure that this actually runs is we

need to call this function that we just

made right so let's go right here and

i'm going to say console.log and we're

going to say how

many

letters okay and let's just call that

function

and there we go okay one two three four

five

and then it ends with um undefined okay

all good so this keeps looping through

and then it just prints out the letter

that's what we're looking for right and

we actually don't even need to call

console.log here because we're printing

out from the function so let's try

running this and now you see there's no

undefined right and we we go from 0 to

40. but it needs to start from a one and

if you think you're getting this or you

know how to kind of solve this or if you

even want to try i highly recommend you

just pause my video right here and

actually give this a try okay go ahead

and try to like do this on your own and

then you can come back to this but i

want you to get a ton of practice with

this stuff because that's how you're

going to get better not just by watching

me but by doing it with me that's how

you're going to get better

so if we want to count the the letters

in here right or this this how many are

in there we can't start counting from

zero okay

so what i'm going to do

is we can just make it where if i'm

getting

uh

a letter here right oh and if you were a

little bit confused like wait how are we

when we run this

how are we getting the numbers

with this four

loop right so you can also say four cons

letter and if you change this to of

because remember i taught you like i

taught you four of loops earlier

so if you do letter of phrase you're

actually gonna and you run this you're

gonna get letters the actual letters

all right if you run um

letter in phrase it's gonna get you the

index at each one of those

right so if you want to get 41 well what

we want to do is

uh just do

letter plus one

okay so this will just increase it by

one whatever it is

and if

and for whatever reason this letter

thinks it's a string so it was doing

that weird thing where it's attaching

you know

zero plus one is zero one and one

plus one is one one it's attaching

itself so it thinks letter is a string

so just type cast it into a number so

force it to be a number

and then

you get this okay so this is like

one very silly way of doing this and you

get oh i get 41 at the end so that's it

that's how i'm getting my

this is how i'm counting my letters but

there are better ways i'm going to show

you in just a second

all right so now let's talk about better

ways of doing this yeah so what we want

to do is

we want to have we want to set a

variable here that let's say is so we're

going to say let

uh result equals zero okay

let's go here and we're gonna go we're

basically gonna say

result is equal to

number and we're going to call index and

we're going to say plus 1. because all

we're doing here

is the loop already allows us to get up

up to 41 right so we know that this is

the correct answer all we want to do

is store that correct 41 in result

and then at the end of this loop

we want to just return that result at

the end

[Music]

that's all we're looking to do

okay so

because okay so i'll give you an example

okay let's just do

result is index

and here let's just return result

let's remove this line

well we can keep that line so you can

just see how the loop looks

and we're gonna run this function but

wrap it in console.log all right

actually we can do a trick here to make

this look really nice so here we have

return result right in order to make it

we want to make it look like this result

is 40. so there's a nice trick we can do

in our return

and we can basically say we can return

it as an object so when you print it out

the object is going to look really nice

like this

right um and then there's a even nicer

shortcut where if you just add in

one thing and wrap it up in an object

it's going to automatically set this as

the key

and

use this as a variable for value so it's

going to set the word result as the key

and use the value 44 from this

so it's a super cool little hack

and you can use this pretty often so

let's run this

and boom you can see that result in this

case is 40. so now you can see that

result is returning

pretty much the last value in this

entire thing that we get right when we

print out our uh indices

so these are this is you know this is

like

basically saying this is zero this is

one this is two but we just wanna start

it off with the one so

um let's go ahead and all we need to do

here to index is

we just need to add a 1 to it and also

remember we need to wrap the index in a

string just like this oh sorry not in a

string i'm sorry wrap index in a number

because it is a string okay so we need

to typecast it

let's run this and boom you get result

is 41.

right so

now

phrase we can change the phrase right

and again

how many letters is a function that

takes in the phrase so let's make this

let's extract this argument out now

and instead we'll put phrase over here

and we'll pass it in the phrase okay so

the function itself shouldn't have to

worry about the phrase it should just

wait for what the user is going to give

it as a phrase and it says result is 41.

now imagine i change this and i go

prompt the user

for

you know

write your phrase

okay and now let's run this and now this

pop-up happened at the top so i'm going

to write my phrase

i am wearing a nice green

shirt

right so when we do that

uh let's go ahead and run this

and i hit okay

and let's see what happens here

let's hit okay

and right when i hit okay boom we got

31.

all right so that

that phrase has 31 characters

now here's something sad i'm gonna tell

you

you can actually replace there is a

method for strings

that allows you to calculate the total

of uh you know see the length of a

string

and that is just

dot length okay

so for example if i well we don't open

up a shell let's just stay here so say i

have a string here

okay let's zoom in so you can see that

better

all right so say i have a string here

that is

banana if i just call dot length on this

and run this you notice it'll give me a

six

okay

and uh let's call let's say

banana wants to know

your slogan

dot length it'll give me back 32 so a

dot length is a property

um

on anything that's of type string you

can call anything that's a string you

can call dot length on it okay

and that returns the final answer

so let me zoom out here which means

which means i could actually remove my

entire code

right

and basically just say

the result is phrase dot length

change this whole thing with one line of

code hit run

write your phrase

it's going to say something crazy and

let's see if it can calculate it fast

and it did and it goes result is 107

okay

but let's write it in our way because

remember that's the way you learn how to

do it and right now it's important for

you to manually learn to do these things

because i want you to develop and focus

on your skill set then once you get

better

normally what you would do

is

you know

a javascript string

um length you will just like google this

okay and see if that exists and you'll

google this and you'll go somewhere and

it will say that let's see

w3schools is usually a really good

resource

and it's just showing you text make a

text let it equal to hello world

let length be text.length and it also

allows you to try it yourself so you can

always click that and you could hit run

right and boom it says 12 here and what

if i change this to something random and

let's hit run

and you can see it says 38

right over there yeah

so

uh this is how you would normally do it

in real life

you just google these things you have to

memorize anything okay

but right now i'm just kind of getting

used to having you get used to exercises

do them yourself okay now let's build it

up and take it up a notch okay so let's

let's make a function

that sums things okay that's also going

to require loops

and arrays

so i'm going to go ahead and we're gonna

comment this out and we're gonna comment

this out so we're gonna go const uh sum

array

it's gonna take in some numbers

and

we're going to have a result we're going

to say

let result equal zero

okay

and then we're going to have some kind

of for loop action going on here and

then we're gonna

return the

result and let's just do this trick like

that we did last time and

something is going to go in the for loop

okay something is going to go inside of

the for loop oh sorry we forgot to put

the arrow functions not bad arrows there

we go and what's going to go inside of

this for loop is basically going to be

imagine this right imagine how we would

do this manually so say we have

these numbers or let's say we have these

numbers okay this we know that this

should if we ever have 1 2 3 4 we know

that this should equal to 10.

now how are we going to actually sum

this up in normal life what would our

pattern be well i probably have some

variable let's just call it result and i

would

set it to

zero in the start or i might set it to

whatever this number is right over here

okay so you could you could do either or

but let's just start it with being a

zero okay so it starts off being a zero

then what we do is we loop through and

we make the result becomes one then we

loop through again and we do one plus

two and then result becomes two sorry

three then we loop through again and we

already have this 3 here so we add 3 to

this 3 right here

so we add this to that

and we get result is equal to 6 and then

we add 4 to that and we get 10. so

that's how we would do it kind of as a

human being if we were to do it like

manually

and do it with each step and that's how

we're going to do it with our computer

we're just going to have it loop through

and keep adding these numbers

so let's go ahead and now write that

loop so again try to give this a try and

see if you can do this yourself okay

because what you've learned so far you

should be able to come very close to

solving this so take five seconds to do

it and also pause your pause my video in

these five seconds to try it yourself so

five four three

two one

all right let's get back to it so here

we go

i'm gonna say

for

const

number of numbers

all right and let's just call console

log number

and uh let's call our function console

sum array

okay and

let's give it an array so we're going to

have we're going to give it this array

of no it's going to be called nums okay

let's remove

let's comment out all of this because we

don't need that and let's pass our

summary nums and let's just run this

okay so we get back one two three four

because it's looping through and

printing number out each time

so if i give it an array of one two

three four it goes okay number is one

the first time print it out number is

two the second time print it out numbers

three the third time print it out so on

and so forth all right so it's printing

this out result is still saying zero so

now what we need to do is we need to

increment our result so let's go ahead

and do that now okay so again try to

give this a try and now we're gonna do

this so all i'm gonna say is i'm gonna

say result and i'm gonna say result

plus

and we're going to do

whatever is the new number that i'm

getting okay

and let's just see if this works and i'm

going to hit run

and it says result is 10. interesting

did that really work well let's try it

with and let's add 5 to this array and

let's see if that works and i'm going to

hit run and we should get 15

and boom result is 15. beautiful okay so

let's see

um

how this is happening what is going on

all right so let's do something to

visualize this code and see exactly how

this works i'm going to copy this let's

go over to

pythontutor.com all right and then hit

enter once you're in pythontutor.com

you're going to go to related services

where it says javascript tutor okay and

click that this website is awesome so

paste your code

and uh just for simplicity sake i'm

gonna remove any console log because we

don't really need that it's gonna help

us visualize so

there's gonna be no need for that and we

don't need any comments either it's

unnecessary for you to remove it but i'm

just gonna remove that for simple

simplicity sake

then hit this big button here that says

visualize execution so let's click it

okay perfect

all right

now

on the left hand side is going to be our

code on the right hand side is going to

be visualizing exactly how this code is

running

very important to notice

also

this red

arrow

means the next line to execute so which

is the next line of code is going to

execute okay so it's already telling us

that this is

going to be when i hit run or when i hit

next to step through this

this is the line of code that the

computer is going to run

and we're just going to go through step

by step and see exactly which line runs

exactly when

and green arrow will mean

the line that was just previously

executed

cool

so this is our function let's walk

through this all right so let's go ahead

and hit next okay

so now it sees we have a function called

summary and

boom it's like okay i got you there it

is there it is i see it let's hit next

again

now it's on const

const nums as you can see right here

right so this is a line that's about to

execute next so let's hit next and it

goes okay i see that there is a variable

called nums and it's inside of this

array okay or it's this array right here

it refers to this array and this is a

global frame because this is

uh these are all variables that are

outside of this function so these are

accessible from anywhere and from

everywhere okay and we'll talk more

about scope in the upcoming videos now

next line is going to execute is it's

going to call this function summary with

the argument nums okay and then our

entire function is going to start

running so let's hit next

cool

so now we're inside of our function and

the first line of our function is just

about to run

so the first line is going to be what

result is

cool

so let's uh right now result is

undefined okay but once this line runs

here result is going to have a value so

let's hit next

and boom result is now set to zero

now

okay so this green is just showing you

the last line that ran

now the red is showing you that we're

about to start running our for loop and

we're just gonna be teeter-tottering in

between

this line the for loop line line four

and line five and line four and line

five and line four and line five until

the entire loop is done then we're gonna

go to this line here and return the

result at the end okay which and again

remember uh you know we're gonna touch

base on scope

but if you put this if you put things in

the wrong scope wrong things will happen

for example if you put this result

inside of this these squigglies here

right this is just going to keep

returning every single result but that's

not what we want we want to return the

results after this entire for loop is

done right and then we want to return

this result okay

so let's run through this and see what

happens okay so right now it doesn't

know what number is either

okay but it does know it results as zero

and it also knows that numbers

refers to this array right here okay

let's hit next

okay

boom

boom boom all right there we go

and now it says number is one perfect

that's exactly what we wanted right

number is one because the first time

we're going through the array right it's

a one that's what that's where the

number is coming from now let's see what

it's going to do the result so watch

what's going to happen it's going to do

result is going to be 1 this time so

it's going to do 1 plus or sorry result

is 0 right now so we're going to do 0

plus the number 1.

okay let's try that and now you can see

result is one let's do it again now

number is two so two plus one result is

going to be three

okay

three plus three result is going to be

six

six plus four result is going to be

10. okay and notice how it was just like

boom boom boom boom it's just these

lines running over and over again right

and now the result is 15 now the loop

ends because are no more numbers to loop

through

and we go to result

result is 15

and then we return the result at the end

return value

right and the return value here in this

case is

this object it was of type object

and it says result is equal to 15.

okay

so there you have it a full

visualization of a for loop exactly how

it works and what is happening and

hopefully that clarifies things for you

a lot further

so i want you to try something

try writing this function some

array by yourself from scratch

and i know we just did the answer

but i want you to give it a try without

referring to this and see if you could

create this function by yourself and if

you could that would be fantastic and

just give it a give it give it a shot

right and if you could get this working

see you know that would be absolutely

amazing and then check back with this

and see how far you got all right let's

do some

more exercises with loops

arrays objects whatever right because

this is going to make you so much better

so

let's make a function called max so

let's do const let's say find max okay

or you could call it max as well

and it's going to take in numbers and

it's going to have a let's say

cons result and then

it's going to return the result

okay and then we're going to have

something some loop stuff happen here

okay some loop stuff and here's how the

algorithm is gonna work okay imagine we

have an array of you know let's just say

one

two

three and four and five okay imagine we

have this array right here and let's

just put commas here

because that's how the array would look

i have these commas and what we're gonna

do is we're initially gonna set result

to one and then we're gonna loop through

and we're going to say hey it's 2

greater than 1.

check these

if it is then result set it to 2.

okay then loop again

all right is 3 greater than two

if it is then set result to this then

check between these two numbers if four

is greater set four if five is greater

set five

and then once the loop is done it's

going to return the biggest number

okay and now imagine if you know in in

let's say there was a case where we had

a

one here

okay let's see if it would work if that

same algorithm would work there

okay set one two the biggest set one

to result okay great

now check between these two's two

greater

yes then make two the result okay then

check between these

is three greater okay make three the

result check between these

is four greater okay make four the

result

check between these is one greater

no

then don't make one the result keep for

the result right and and then that's how

we're we end up with four so that's kind

of the algorithm that we would do okay

now we just have to code it up so we're

basically gonna say set result not to

zero okay because imagine

what if you had an array with only

negative numbers in it well then zero

would be the biggest number so that's a

common trap do not set result to zero

we're gonna instead say

results is the first item of this array

okay we're assuming we're getting back

an array or we're getting an array here

okay

and then we're gonna say is loop so

we're gonna say we're gonna write a four

of loop const number of numbers

and basically we're gonna say if

number is

greater than result

in that case what do we want to do

we want to set result

to that number that we just found

and at the end

when we're done with this loop we just

simply

return the result okay so let's go ahead

and give this a try

and let's comment out anything else that

we might have running okay we don't have

anything else running so we're oh we do

so let's

comment out these lines right here and

let's just go console.log and i'm going

to say max and let's give it numbers

like one two three four

five

and let's see what it returns as the max

aha yeah so this is not a const let's

make this a let because we are going to

be changing result okay so this error is

saying assignment to constant variable

so all it's saying is hey you cannot

redefine a constant so that's why i'm

changing it to a let now you can

redefine it right here and we should be

good and let's do that trick again let's

return result as an object so it looks

nice when we print it and you can see

result is five now imagine we have one

comma two one two

so the max in this array is what

it is a

it's the 4. so let's

see if it gives us a 4.

yes it does beautiful look at that let's

go 20 now

and 10.

and let's see if that works beautiful

and now let's make this array

now let's make this massive right like

let's just

uh

yeah let's let's take this right here

and let's just paste a couple of times

and run it and look at that it says

result is 20 and if i make this

a 3 over here and run it

boom result is 30. i mean it will find

it wherever the max is it will find that

max right so this is a really nice

function that we have created now let's

keep building on this okay so this is

all going to be making sense and trust

me it's going to be so important for you

once you start getting to

building projects and doing those types

of exercises you're going to wish that

you spent the time to learn this because

this is going to be a complete game

changer for you all right so our max

function is done

let's work on a different function now

and what this function will do is

it will

calculate frequency okay so let's go

ahead and try that so we're going to

const

frequency

okay it's going to take in

uh let's say a phrase

that somebody will say and i'll tell you

how many times

uh that phrase or that or sorry that

that letter occurs okay

so let's just say

letter frequency

okay so what does that mean so say i

said

haha

here's what it should return

okay so if i call the function letter

frequency on the word haha here's what

it should return it should return

an object and the object should say h

occurs twice

and a

occurs twice

that's what it should return so

how do we

create this function so it does that if

you want to give it a try you can this

will be hard because you'll need to use

your object knowledge as well that we

put together a while ago

but this will be using you know summing

up numbers looping through things

iterating and all kinds of stuff like

that and so

uh incrementing variables is going to be

a tough one if you try to solve it

yourself but you should give this a try

right about now and we'll continue in

five seconds five four three two one

let's continue

so i have letter frequency how do i

determine this

okay let's figure it out together

first let's just go ahead and call this

function so we're just going to say

letter

frequency and we're going to give it

that phrase haha like this

and uh let's console log that phrase

let's delete that line and let's just

make sure that this letter frequency is

running okay haha showing up perfect now

what do we want to do

we're we're getting haha

well we need to actually start writing a

for loop that will start going through

all of those letters because that's

going to be important

okay

so let's go ahead and write a for loop

so i'm going to say for

letter const letter

of phrase and let's just go console log

and we're just going to console log each

letter and let's see what we get

we get h-a-h-a

okay great now this is where objects are

going to start becoming very very handy

because you know key value pairs are

going to be absolutely clutch for this

um arrays are not a good solution for

this okay but like objects are objects

are also great for storing you know

information in your phone book like on

my iphone

when i'm going through that is being

stored in an object okay that's why i

have you know my name

my you know i could look up somebody by

their name their phone number etc and

objects are great for that so we're

gonna go and look at something in the

console okay and that's gonna make our

lives a lot easier so say we have

something called

word and this word has let's actually

give it let's actually call it frequency

right or freak

um

and let's say this frequency has

that the h is

once

and that's it okay so it has one h in

there now if we have a word like haha or

whatever right or if we want to just

check

yo is h inside of the frequency

we're actually able to check that and it

goes yes h actually exists because it

can if you do h and frequency what it

does is it looks for

h as a key

ins and searches all the keys inside of

an object okay so it goes yes h exists

and uh if i go

you know because of the word haha does a

exist in frequency and when i look it

says no

that a does not exist that's actually

false

so using this we're actually able to see

if we've already stored something in our

object or not because the way that we

want to do this is we want to go and say

okay so say we have the word haha then i

want to have a object

i'll just write it out here and it

should loop through

and in the first loop it should notice

that there's a letter h so as soon as i

notice the letter h i make a key for h

all right and because i know it showed

up once i set it to one so i go that key

is equal and it's it has a value of one

now

then i loop through that

other word again and this time i see

that we have a okay perfect

well have i seen a before

no i haven't so then i set a to 1

and so far so good

okay then we loop through the third time

and i see h again well i've already seen

this before

so what do i do if i've seen this before

am i gonna go ahead and make another h

and then set that to one you can't do

that because in objects you can't have

the same key repeating twice so we have

this key here and that this key here so

what will happen instead is we will end

up overwriting this key

and just do h as one and that's what it

was in the first place but that's not

the result we want we actually want to

we actually want to increment this key

right here

this h1 right so we want to increment

this one

by doing plus one and making it a two so

how do we do that what we do is we go

hey does h already exist and we do this

little checker here right there

and if it says yes h already exists then

we go go to h

and

and add one to its value so it goes okay

i'm to go ahead and i'm going to do that

so we go to this and this becomes a 2

right and then we go to the fourth

letter in haha

and we do the same thing and we go hey

does a actually exist in frequency and

in this case it's supposed to be a true

and it goes yes a does exist and so if

that's true

we then go okay find the existing a find

its value and increment its value by one

and then we get 2.

okay so that's how that works that's how

that works

so let's go ahead and basically say that

algorithm

but in code this time

so first we're going to make a frequency

make a frequency object

and that's going to store all the memory

slash all the data of what it has seen

so far

okay so this is so make a frequency

object okay it's going to be called

frequency kind of like we did here okay

but in the start it's just going to be

empty it's going to be an empty object

then we obviously loop through all the

letters of the phrase

and we check if that letter that we

found in phrase does that already exist

in

frequency so

check if letter exists in frequency

so you make sure to you know we're kind

of writing pseudo code right now because

we're just writing it kind of like code

but in english and then later you just

turn it into

code and then you're done so if we check

if the letter exists in frequency okay

what next

well if it exists remember if it exists

we're gonna increment by one

otherwise we set it to one

so let's write that check if letter

exists in frequency

if it exists so this is going to be

indented because this is going to be

nested inside of this if condition and

we're going to say if it exists we'll

then

increment

the value

by one

otherwise

set it set

the value to one

okay that's essentially all we're doing

and so now take take some time to see if

you can actually write this as code and

then obviously at the end we're just

going to return that frequency that we

created okay so we're going to return

that frequency so const or let's go let

frequency

equal an empty object

so see if you could code up the rest of

this okay take maybe

a minute or five minutes or whatever and

even if it takes you 20 minutes it's

totally fine because this is normal okay

you're not supposed to get it this fast

this is supposed to take you a lot of

time

but take some time i'll give you five

seconds to pause the video and try it on

your own five four three two one

all right let's do it together now

check if the letter exists i'm going to

say

how do i check well i just checked by

doing letter

in frequency okay does that letter exist

in frequency this will evaluate to true

or if false that's it i'm going to say

if

letter is in frequency

then

do the following

and then we're going to say increment

the value by plus one so how do we do

that let's do that right now

we're just going to say frequency

of that letter so we're creating a new

key on the fly

and we're gonna say equal to

whatever it was before

plus one

okay so it's like whatever frequency

of the letter previously was just like

incremented by one okay if it doesn't

exist which is the only other scenario

then what we can actually say

is we can go and say hey set the

frequency

of that letter

to one

that's it

and uh then we just return that

frequency okay so let's try it on this

word

haha and see what we get

and look at that we get h is 2 and a is

2.

that's crazy right like we just coded

that out from scratch and it works so

nicely and let's try

lol what are you

doing

later tonight lol

haha

okay

let's run this

and it just runs through every single

letter right here

and it says l happens about five times

is that true let's see

l

two so one two

and then we got

three

four five yep so that looks like it

happens five times and it says how many

times o happens and it says how many

times a comma happens how many spaces

there are

and it just shows you the whole freaking

thing right

so

frequency is working as expected now one

thing i'm going to show you is called

incr these are incremental operators

okay at least that's what i call them

and they are plus plus

minus minus

plus equals

okay

um plus equals one and so these are

incremental operators they're really

really helpful and make everything

shorter so for example this over here

you won't ever see it written like this

if somebody's coding this up they're

gonna write this like this

okay so it's gonna say plus equal 1. so

plus equal 1 is the same thing as

frequency letter

is equal to frequency letter plus 1. so

these two are equal and i just want you

to kind of get used to seeing them okay

and we can go and change

some of our stuff

above as well so like where it says

result equals result plus number

right

how could we change this here

try it on your own take about five

seconds and this you should be able to

do in five seconds five

four three two one

you could change this with a plus equal

all right

incrementing it like that okay

and if you're incrementing something by

one here's the cool thing you could also

just do

frequency plus plus

and that just this just means that

you're incrementing frequency by one so

let me try hitting run

you can see that this works right

you can hit one run on this and you can

see that this also works and gets the

same result

and we can you know

or you can go back to the oldest one and

see we get the same results so it's a

matter of preference you never want to

write it the long way

you won't ever see it written the long

way and you could write it in between

these two ways so you could go plus

equals one or you could go plus plus

either work

okay so i just thought you should know

those you could also go minus minus and

that will like decrement it

okay and um

you know

so i'll just leave this as plus equals

one for you just so you can wrap your

mind around this

and get used to seeing it okay so these

are incremental operators they're very

very useful and

very commonly used

now i'm going to remove all these

comments or i can just leave them here

if because you know this might

this might kind of

hurt your brain a little bit how's this

frequency thing working so i'm going to

leave that here for you all right now

let's just keep building on this and

let's keep taking it a step further so

now instead of letter frequency

let's

improve our our skills and and do

something called word frequency okay so

we're going to build a new one i'm going

to say const

word frequency

and see if you can try to challenge

yourself to take a stab at this phrase

and then we're gonna run this function

okay

and we're gonna do the similar similar

type of approach we're gonna create

frequency here as an empty object and

we're gonna return frequency at the end

all right

um and

inside of here we're gonna do our like

coding okay this is where we're gonna be

doing our logic now

here's the one interesting part here

i'm gonna comment this out

obviously let's comment that out let's

go ahead and console.log word frequency

to make sure it's running

and let's give it a phrase the phrase is

lol

what is going on

lol what

law let's just say that okay lol what

lol

so we know that if we run that here's

what we should get so

if i run this function so let's have an

example and this is also really good for

documentation because

by looking at this people can know

how to call your function and then what

your function actually returns at the

end so i'm going to say word frequency

and if i call this function with this

phrase law what law

it will return the following it'll say

lol

occurs twice

and

what occurs one time

okay just like that

and um this is what it should return

so how do we make it so it does that

well i wanna i have to teach you a

couple of things for this so say i have

a phrase

and let's go phrase is equal to lol what

lol

so what we would really love

for to happen is imagine we had an array

and

it had a it had things like this

that'd be really nice because if we loop

through something like that right in an

array it would just

loop through the words and we want to

loop through the words instead of

letters that's the only difference here

between last exercise and this exercise

okay so how

then the question is how do we get it

into an array so we can loop through it

because

if you try to loop through it in a

string watch what's gonna happen okay so

if you try to loop through in a string

it's gonna loop through and print out

every single letter from here

so let's try to write a loop and loop

through this so i'm gonna say

four

letter

in phrase

console.log letter

okay and we're gonna hit enter we're

gonna close the parentheses and run this

right and it's just gonna oh sorry not

not in let's run that loop again and say

of

of

and it's just going to print out every

single letter well that's going to be

confusing because it's going to

count letters for us and instead what we

want to do is we want to count words

entire words right and words in this

case are separated by what what's a

common thing all of these words are

separated by take i'll give you a hint

they're separated by

these spaces

okay

so we can do something cool in

javascript we can turn this into an

array

um

and if we turn this into an array so

let's say i give you phrase and if i

call dot this method got split on it

it's a string method and i say split it

by spaces

and i hit enter watch it what it's going

to do it's going to turn that into an

array and now that array very clearly

has three items and if i loop through

through these items watch what's going

to happen so

i'm just going to call it array

okay and then let's just loop through

there's a 4

word in array

console.log

word

i'm sorry i'm just used to python so

it's for of of

of of

so for word of array

yeah law what law so look at that i'm

actually looping through

the words in that array and i can now in

my object see if this word exists and if

it does exist then i can increment it by

one and if it doesn't exist then i can

just set it to one so it's the same

exact thing but just with words this

time and all you have to do is turn it

into an array of words and then you're

good so let's give it a try now

is what we know so we're gonna once we

get our phrase

okay what's the first thing we're gonna

do to it what's the first thing we're

gonna do to that phrase to turn it into

an array

we're gonna do phrase dot split

yeah this is going to turn it into an

array but we need it to be separated by

what it's separated by spaces in this

case okay

so boom

this is going to give us what we need so

now let's

let's go ahead and um

i'll do

let's just call this words

okay

and um

now

let's console.log

these

words and hit run and watch what happens

now i hit run and watch i got lol what

lol okay

if i have hello here and i run it

lol what lol hello yeah so now it's

doing what we want it to do now the

algorithm is going to be pretty much the

same as letter frequency

very very similar to that so we're going

to basically use like a similar

similar formula okay that we did here

so we're gonna say

we're already creating that frequency

object there yeah

and then we are returning it that's good

so we're doing that here too we're

creating it and we're returning it so

that's good

and we're gonna do the same thing so

we're gonna say for const word

of words

okay let's just console log the words

for now and let's just see

what it's console logging so let's run

it

and you can see that it goes lola what

law perfect is

every word and we're gonna do the same

thing check if it exists in the

frequency if

word and frequency

then

we're going to say

we're going to increment it by one

so we're going to go

frequency

word

plus equals one

else

frequency

word

set it to one

and at the end return frequency so let's

try this

and boom look at that lol is twice what

is one time and it's already working

right that's crazy so let's go

yo yo yo and let's run it and here we're

gonna see that yo is coming out three

times lol is coming out two times and

one is what is coming out one time so

i mean this is so cool we just made it

but

there's something we can do to make it

even better

i want you to notice the similarities

between this

and the letter

frequency thing that we wrote yeah and

instead of calling it letter frequency

let's just call it i mean actually let's

leave it as letter frequency that's fine

but they're very similar right the code

here is very very similar to the code we

have here for example

we're creating a frequency object we're

creating a frequency object

we're returning frequency

we're returning frequency

right

we're

we have a loop that we go through we

have a loop that we go through

if it's detected in the frequency

incremented by one

if it's detected in frequency

incremented by one

if it's not detected set it to one if

it's not detected set it to one i mean

my gosh there must be something we could

do because

it looks pretty much like the same exact

thing

and watch there's something brilliant

that we can do so we can actually delete

this entire for loop

let's get rid of this console log

we can delete this

let's get rid of this return here

let's get rid of this frequency here

and the only new thing we need in this

is we just need to

split it by

uh spaces to break it into words

right and let's go const words

sorry i keep forgetting the cons

sometimes

and all we do here

okay this is going to be so beautiful

is

we call our letter frequency function

that we created earlier and we just pass

it words

and then ill know what to do with it

so it goes in here

and then it has instructions for what we

need to do

right and all we need to do here is just

say return

so let's try running this

and look at that you guys we are getting

the same exact answer and it is

completely correct yo is three times

what is once lol is two times okay

now

this is if this is not blowing your mind

think about it like this when you go to

google right and you type in kanye west

and it starts auto completing it's using

the same thing because it knows

what are the things that are being

searched frequently

and because it knows their frequency

it's showing them here so for example

maybe this search over here

right this kanye west runway

that might be done let's say 10 times

kanye west net worth

might be done five times

kanye west's girlfriend might be

searched three times

okay it's just an object and then google

is sorting it and showing you based on

the ones that were the most frequent

that's the really cool part and this is

why

you know once you learn this here all

you need to do is be able to attach a

front end like this and boom your apps

are going to be absolutely amazing and

mind-blowing so let's try this now okay

let's try our own function with

different inputs we're going to say

const user input is prompt

uh write your

sentence

right and we're gonna replace this with

whatever the user types in so we're

gonna say user input here

and call this and um

yeah let's go ahead and run it write

your sentence and we're just gonna say

um

[Music]

kanye

west

has great music

but west side

is

greater

than

greater

than east side yeah because i live on

the west coast in california and then

you got all these people in new york and

i like that my time gets back

i get my three hours back when i come to

california instead of losing my three

hours when i go to new york so

if you're in new york

and you want to earn three hours

back of your life forever come to

california

so let's try this

yeah and um

probably the only thing that occurs

twice is

west i imagine okay

and then let's just write kanye is also

the goat

the goat

that's not gonna work the goat okay ella

said the goat

and let's hit okay and run it and uh it

came back

all right and it broke it down

and you can see it did a full breakdown

of every single word kanye is two west

is two

has is one great is one music is one but

is one side is one is two

and the goat is two thus two and it did

it all so fast and so quick

all right so we did a lot of

challenges and exercises and if you want

to deep dive and do like a full on boot

camp and master arrays

and objects then i recommend you

deep dive into exercises okay where

we'll have

additional exercises for you and lance

he is going to be your boot camp

instructor for those okay so if you want

to become a like a legend he's going to

help you turn into a black belt my job

is to take you from white belt turning

into a blue belt he will do that so if

you want to for example you know because

i'm going to move on to different topics

now but if you want to just keep

exercising this

you can do that

you can do that by going into say this

exercises folder on the left hand side

by the time you're watching this

tutorial we'll have bunch of more

exercises right now we have this one

here that says convert convert hours to

seconds you click that okay and then

lance has this exercise prepared for you

there's a rebel that you'll have to copy

okay and paste in your urls and you'll

be able to fork this and be able to code

it on your own so this is the rupple

that lance has created and if you want

to be able to do it on your own hit fork

at the top okay

and then you can actually run this

uh rebel

okay

and uh you can write your code here and

you could write your solution here okay

and

what lance will also be doing with some

of these exercises he'll also have a

link at the top of the loom video where

you'll be able to click and watch his

video explaining that exercise

explaining that project in detail as

well okay so

think of him as a

solid

um you know

boot camp instructor that just like kind

of dives deep in with you all right so

that those are going to be the extra

resources available to you with that

said

with that said

you're doing amazing

pat yourself on the back i mean wow

you're doing an excellent job so far by

being here you're putting in the work

you're putting in the effort i mean you

could be doing so many things you could

be playing with your kids right now you

could be

outside hanging out with your friends

you know

you probably got off of work and you're

putting in that time to learn this i

mean that's huge dedication you're

taking time away from all this other

stuff you could be doing and doing this

so now granted coding is a lot of fun

but if you're in this stage i know

you're doing it for learning and i tip

my

proverbial hat to you

um huge props for making it this far

with that said let's keep on rocking and

rolling all right now we're gonna move

on to something really fun they're

called higher order functions don't let

the name confuse you or freak you out

they're very very easy i swear once you

see them a couple of times pattern

recognition maybe and then it's so fast

it's so easy so let's get to it so there

are a couple of higher order functions

i'm going to show you okay so higher

order functions and i'm going to show

you map and i will show you filter map

is like one of the most important things

that you should use

uh i'll also show you reduce okay and uh

map will make your life so much easier

like you'll be using map so much and

then you'll also use filter a lot when

you're writing javascript code so let's

go ahead and comment out these lines

here because we don't need them right

now and let's just get started okay so

we want to use let's start with doing

some of these functions again but

instead we're actually going to use map

so let's say we want to double our

numbers right any number that we give it

watch how easy it is so say i have an

array i can

loop through this

using dot map and i can say map and give

me a number and for each number i'm just

going to console.log it so watch what

happens let's run this and boom there i

have my loop like look at how clean it

is it's just one line right no blocks of

code no weird squigglies or anything

like that and what i'm what i'm saying

is

map through this i mean literally think

of it like loop through this like it's

literally like dot loop and then each

variable let's we'll just call it number

so like this will be a variable called

number then this will be number and this

will be number and each time what i want

you to do is just print it out so

i'm returning this right away but if you

wanted to write a full function here you

could just do this put open close

squigglies and like write whatever you

want here okay you could write multiple

lines here and when i run this you'd see

it's like one haha two haha three haha

for haha like so on and so forth so

let's remove this now we're doing an

implicit return implicit return by not

having a squiggly braces here we don't

even need to say return it's

automatically returning it okay now

i want you to take a look at this how

could we double all of these numbers

here watch how easy it is i could just

say number times two and watch what

happens so let's just go

let result is equal to that and we'll

console log result

okay let's run this

and look at that you guys like that is

so clean that is so nice i mean it is

the easiest thing right in the world and

it just boom two four six eight and all

i did is i just said number and multiply

that by two now here's also what's cool

about map so whenever you have to write

loops pretty much just forget about them

and you'll be using maps like most of

the times in javascript most of the

times and what's cool about map is it's

also returning to you an array okay so

map

returns

so it loops and returns

an array so remember when you have to

like make this result thing

so for example when we were doubling our

numbers right we had to make this result

and this temporary array then we had to

loop through and push to that array and

then return that array well what's

amazing about

map is

it's already doing that it just goes

through and doubles it it's

automatically pushing it to an array

right and then it's returning that array

at the end

so that's what makes map so freaking

awesome and all of our like code that we

have written before we could just like

replace it right so let's let's rewrite

our double functions let's say const

double map

and

it takes in numbers

okay and what this does

is it will take numbers so we'll do

return numbers dot

map

and for each number just multiply it by

two

okay so that's it

that's our entire

function so compare this double here

with how many lines of code to this

double here with one line of code this

is so much cleaner and so let's delete

that

and let's try running

double map

and give it an array we'll say one two

three and we should get

two four six

boom look at that we got an array of two

four six so this is a much nicer way of

writing it so i

try turning some of these okay for

example

you know some of these functions into

using map

or

using filter and see if you could do

that all right now what i'm going to do

is before we get into the exercises and

remember for exercises if you need

exercise there'll be an exercise folder

for you

me or lance will put together these

exercises for you and you can always

kind of access them from here and

exercise okay and by the time you look

at this it'll be much more fleshed out

so

i showed you an example of how to use

map

so this is

map

all right now i'm going to show you how

to use filter okay that's another

important one so say you have numbers

like

one two three four five six

well in order to be able to go through

these numbers i mean

and and let's say i want you to only

give me numbers that are greater than

three how are you gonna do that right

now

let's create our own filters we're gonna

say const filter and it takes in numbers

and it takes in a filter number as well

so like

should be greater than or something like

this okay so we have to give it a few

things we need to give it numbers and we

need to give it like it should be

greater than 4 or greater than 5 or

greater than 3 something like that and

then how will it work well

we will need to have an empty array to

start off with and then what we need to

do is go hey is

one greater than this number here

and

if one

is greater than this

then throw it in that bucket but if it's

not let's say we have we chose 3 to be

our number here so 1 is not greater than

3 right so then it shouldn't do anything

with it and cross it off

then we go here is 2 greater than 3 nope

is 3 greater than 3 nope is four greater

than three yes so then you get four it's

five greater than three then you get yes

is six greater than three yes

right so you pop those numbers in there

but besides those you don't so then you

get this filtered array okay so if you

run filter

and let's say we give it

uh numbers let's say we give it a

you know one two

three

four five six

and then we say it has to be greater

than three

well then what should filter return

it should return

four five six that's what it should

return so see if you could

write this function on your own okay so

i'm gonna give you five seconds to pause

the video and try giving this a shot on

your own five four three two one

all right let's do this function

together

so i have filter here

now

what we can do is um we have our numbers

we have what what it needs to be greater

than

so we're going to start off with an

empty array so we're going to say result

equal that empty array let's actually

write our for loop first so let's return

the result and let's write our for loop

so we're going to say 4

number of

const number of numbers

i want you to do the following

if

number

is greater than

this number

then

we're going to do result.push

number and then we're going to return

that array at the end all right so let's

give that a try now so we're going to do

console.log

and we're going to call our function

filter

we're going to give it an array of one

two three four

five six

right and then put a comma here and

let's give it another argument and the

greater than number will be three so

let's format our code and let's run it

all right and then filter work so it

gave us greater than four five and six

so here we've kind of created our own

filter this is like a manual way of

making a filter and it's all right it

does okay job if we need you know for

example let's say we give it a two well

then it should give us number three four

five six let's run it so now it's only

looking for numbers greater than two so

boom it it works

but

let's use the dot filter method and dot

filter is an array method that we can

actually use and it makes our life a lot

easier okay so watch this what we can do

is let's comment this out right now and

i can actually go and create nums okay

so let's say we create nums one two

three four five six okay and let's

filter through this so let's say

nums.filter and i'm gonna say for each

num return to me

make sure num is greater than

six all right let's console log this and

here's the cool thing about filter okay

filter returns an array all right that's

the cool thing about filters so if i go

back to filter here it also it loops and

returns an array with matching

conditions

so that's the difference between map and

filter map will return the exact thing

and filter will loop and return an array

with matching conditions all right so

let's give this a try and let's console

log this

and let's run it nothing is greater than

six so that's why we got nothing back

let's try three boom four five six let's

try uh let's try greater than or equal

to this so if we do greater than or

equal to then how many items should we

get back take a guess

all right if you said four good job

that's right it is four great work on

that but it will return four because

it'll be

four five and six because they're

greater and this is equal

greater than or equal to so let's run it

one other thing with conditionals that

um you should know about is uh operation

called and and all right so

the and logic is really important for

you to learn so let's go ahead and look

let's just practice this here but if you

have true or false watch what happens if

you have these statements like this

right if you have true statement or a

false statement

you can have so

if you have this this will return a true

and how you write an or

is like this in javascript if you do

true or false it's going to give you a

true if you do true

and and

and false you're going to get back or

false all right so these things are

important for you to know they're logic

tables and i think it's much better for

you to just understand them by example

because if i tell you logic tables

you're going gonna be like oh my god

logic tables what is that well it's a

lot simpler than you think so for

example say i want numbers greater than

four

so i want numbers greater than four but

i also want numbers

uh that are less than three or less than

two let's say how can i say that

statement well i can say it like this

let's go or and now if i run it it's

gonna notice that it gave me a five and

a six so those match the conditions and

it gave me a one because one also

matched the condition so

anything that's a or statement here's

the cool thing about or it needs to

match this

or this it just needs to match one of

them and if it's the case then it'll

automatically be true

just needs to match one of them but if

you said and

right if you put a and here logical and

like this it won't show anything you

know why because nothing matches that

nothing is greater there's no number

that's greater than five and six and

less than two at the same time this

wants both to be true at the same exact

time so here we wanna put an or examples

of these could be like let's say a user

is authenticated right in an app

and then

user

is

a

premium

member you know or like

and

user is paying member

so

then you want something to happen right

so you can go if then you want to run

some like piece of code that that let's

just say does something okay so if user

is out and then like code goes here so

if user is authenticated and user is a

paying member then do the following so

this is an example so if this evaluates

to true and this evaluates to true

that's the only time this code is going

to run but let's say the user is not a

paying member and this is false

then you know for example let's let's

make a let's make an example here let's

say you're a youtube user right and you

have youtube premium so if you have

youtube premium then i show you

no ads

so if you're authenticated logged in and

you're a paying member then i show you

no ads otherwise what i do

show you ads so that's the nice part

about this and and thing

so if i can even make it like this right

equal true and this is equal to true so

that would be like more verbose way of

saying it but this is why this chaining

kind of comes in but then like doing the

same youtube example maybe let's just

say that let's remove the ads like let's

say the youtube app deciding when to

show you the videos so if i go to

youtube oh i can't go to youtube right

now because i'm in focus mode so you're

just gonna have to imagine that we're in

youtube because i'm a human being right

like i'm sometimes making these courses

for you and these exercises for you and

then i get distracted spend a bunch of

time watching youtube and it's just it's

just a waste of time right and i end up

not making this course material for you

so i have to stop myself and block my

own youtube so there you go that's what

you saw i've blocked my own youtube and

this is what my current focus is so

let's just go back because i don't want

to fall down the youtube rabbit hole but

just imagine in your mind's eye right

what happens if you're authenticated you

be white we might want to relax this

statement and put an or here why you

know show youtube videos so

whether the youtube user is

authenticated or whether the

user is a paying member in either case

they still get to see youtube videos

regardless but let's just say you might

have to be logged in so that's why the

or so the aura creates relaxing

conditions easier to match and creates

these strict conditions that are like

district disciplinarian father okay so

use them accordingly

they both have their own use cases uh

but they're very important to understand

like the and and the ors okay and they

come up quite often so here i can using

this

i can find numbers below a certain thing

and numbers less than okay all right so

let's make this example a little bit

better okay oops did not mean to do that

cool let's go back down all right let's

make this example a little bit better so

what can we do with this okay so say we

create a array of objects so this is

where it's going to start getting really

cool because in reality you're always

dealing with or mo a lot of the times

you're dealing with array of objects

when you're using an api or whatever and

i'll show you what it looks like so say

you have actors right and you want to

have actors with their net worths and

then you want to

filter based on their net worth so only

show you like the richest actors versus

like the actors that might not be that

rich yeah so let's say we create an

array yes first thing we're going to do

is we're going to create this array and

then inside of this array we're going to

have we're going to create an object and

we're going to create a name and let's

say johnny short for johnny tepp and

then we're going to give johnny depp a

net worth of whatever that is let's say

amber uh net worth of 10 and then uh

let's create create leonardo

with a huge net worth so whatever that

is 100 million cool so we have an array

of objects okay so when you have an

array of objects what you can do through

it is you can loop through it um kind of

in like a normal way if you wanted to

but i'm just going to go and show you

how to make that filter example that

we're talking about okay so what i'm

going to do is i'm going to say

actors.filter and i'm going to filter

them and i'm going to grab each actor

and i'm going to filter them based on

their net worth anywhere where their net

worth is greater than 10. so if it's

greater than 10 show me those actors so

guess which actors it's going to show me

can you take a guess i'll give you five

seconds five four three two one

you're absolutely right it's only going

to show me johnny and leonardo it's not

gonna show me amber because after that

lawsuit she ain't got no money left

right so let's hit run on this and we

see leonardo and we see johnny and we do

not see amber right let's go ahead and

comment this out and i'll also delete

this line here because we don't need

that anymore so let's run this again and

you can see that i have johnny and

leonardo right here so you can see how

powerful filtering is right like it is

able to go through an array of objects

and it's able to filter based on the net

worth and then based on that it's only

returning it's creating a new array of

objects and it's only returning the

objects

that

have a net worth of greater than 10. and

we can keep taking this further now what

i want to show you is

we can not just keep everything in

console logs right but we can also put

things to the dom so we're going to get

a lot more into dom elements later but

right now let's just do a little sneak

preview so what i'm going to do is i'm

going to say playground dot inner html

and um we're gonna now output this stuff

to an html okay so i'm gonna say

internet html and i'm just gonna say

leonardo okay let's start with this and

end the h1 tag perfect now let's run it

and you can see

it runs it right over here the next

thing i want to do is right now it's

hard coded i'm get how i'm getting his

name so let's actually write a piece of

code where we can dynamically get this

name over here okay so let's go ahead

and instead of console logging this

result i'm going to store this so we're

going to say const result okay or let's

just say let result and we're going to

store it in here and then here

let's make this a template literal where

it says hard-coded leonardo we're gonna

make it javascript i'm gonna say result

get me the zeroth element from the

result so that's gonna get me the

first thing all right and uh then i'm

gonna say

dot

actually i don't need to do yeah yeah i

can do dot name okay result zero dot

name so that'll probably get me johnny

depp let's run this okay sometimes if it

breaks like this just refresh and

everything should be fine so i'm gonna

go ahead and refresh

okay perfect so now you can see that

it's actually getting me

johnny kind of how i expected it would

let's go console.log and we'll see a

result here as well so you can see all

right and johnny net worth is 200 to

whatever two million right and then

leonardo dicaprio net worth is 10

million and uh i'm able to get johnny

right here by doing result zero dot name

dynamically if i wanted to basically see

let me actually run this again if i

wanted to see the entire object like

this entire thing but output it onto the

dom

i could stringify it so i can actually

go

hey get me the result and then we'll say

stringify json. let's go json.stringify

and then we'll pass in result okay and

let's run this and it'll just kind of

like output it kind of like that which

looks pretty hideous so we want it to

look a little bit better right let's

start off with just showing the names of

the people that have a higher net worth

than let's say

two million so basically what i'm gonna

do here is i'm gonna do the following

okay so let's let's go ahead and run

this so what i'm going to do is i want

to make it so it just gives me the names

of each person okay and how can i do

that so say i have an array like this

let's store that in results i'm going to

paste that here so let's whenever i type

in result i should get that well how

will i

join them

what i can do is i can actually map

through this because map will return an

array and so i'm going to map and first

i'm going to get this element and i'm

going to get this element and all i'm

going to do is i'm just going to pull

out the name so what i'm going to do is

i'm going to say result.map and i'm

going to say for each actor in there i

want you to just return to me actor.name

so this is just going to return this

code here saying return an array with

just actor names that's it so return an

array map is saying return an array

that's just filled with actor names

that's it that's all i'm doing so let's

run it and boom i'm just getting this

back even if i do that that should get

me kind of the right result now what i

can do on top of this is when you get

this array back you can actually call a

method like join on it and if you join

it it'll actually join it and turn into

a string so it's the opposite of splice

splice turns it into an array the join

will turn it into a string so i'll

actually say the join

and then join them by either spaces or i

can say join them by a comma and a space

right so now it's going to be johnny and

leonardo and no matter how many actors i

had it would kind of join them by name

with a comma and a space in there so all

i need to do to this thing that we had

written earlier and i was just pressing

up so i could find that and i'm just

going to say dot join and we're going

gonna put this here and put a comma

right there i'm gonna hit enter and now

just doing the whole thing all in one go

so

let's copy that line and we're gonna do

it right here okay

let names and i'm going to say names are

you know whatever result was we're going

to map through it for each actor just

get me the actor name

so again

get me an array with actor names that's

all i'm saying here and then join it

by a comma and a space and then those

names

i want them

outputted on my

dom so let's hit run

and you can see that i'm getting those

names out put it on my dom okay let's

add in a couple of more actors here

so boom boom

boom

so let's look up matt damon networth

all right celebritynetworth.com perfect

so 170 million all right 170 million

let's type that in

170 million let's type it in so we can

copy the right amount of zeros here

let's copy that let's move it back and

i'm going to say matt

we'll put that right there so his net

worth is 170 million let's uh grab

another actor let's go

brad pitt

net worth

okay and we got 300 million here perfect

so let's go 300 million and

we should get

calculator.name nice

good website good website and i'm going

to copy this right here

and we'll paste it right there just

remove the commas of course

all right so we'll name this one bread

red okay that's it and let's remove

this one because that's a duplicate so

this is this is good for now

and um

let's let's just run this yeah let's run

this and see if it works

and so any actors that have a greater

than ten dollars net worth you got

johnny matt brad pitt and leonardo

dicaprio

and you know the whole thing works

perfectly and what's cool is like if you

wanted to show images for them you could

also show images you just need to store

image url

all right so i think these exercises

kind of pushed you

a little bit when it comes to filter

like if you had to write this code

without using filter or map oh my god

like good luck try it and it will be so

many lines of code there will be so many

functions

with filter and map i mean they just

make it so easy to kind of just like

go through this so i'm going to comment

out all of this comment out this going

to comment out all of this right here

so when i run it nothing really should

be coming up perfect

so now what i want to show you i want to

show you reduce okay this is the another

one that's really really important

so when is reduced used

let's say you want to combine all of

if you want to sum all of the net worths

okay so generally whenever you're

thinking of summing

it's a amazing use case for summing like

whenever you think some

think

reduce okay and i'll just try to teach

you with examples because that'll just

make it so much easier for you to learn

so say we want we have that function

where we sum right so let's go ahead and

find our sum function

so where do we have it

some array

all right so

we have this function some array look at

how many lines of code this is right now

watch what is going to happen when i use

reduce

okay when you're summing an accumulator

like this that's when you use reduce

when you are

doing something else where you need to

return an array you will use

map okay so push gets replaced by an app

all right so let's see if we can turn

this into a very small lines of code

like summing an array of numbers

here's how this will look okay some

nums okay some

with reduce okay so i know it's a big

name but this is still a set the you

know simple function and i'll show you

how it works

and here's what we're gonna say

okay so we're gonna get numbers

and we'll do

we'll have it do

numbers dot reduce

all right so to keep things simple let's

uh not even have it be a function okay

let's just start actually let's do it

right here on the right hand side first

so say i have one two three

okay how do i sum them up

so here's how we're gonna do it

with this okay so let's say i have my

nums okay so let's say i go nums are 1 2

3

and then i'm going to say reduce

okay and reduce takes in a function

reduce takes in a function as an

argument

that's why it's called a higher order

function

because

even if you look at filter i don't know

if you noticed but what you're really

giving filter here

so

uh let's just go back you know just in

case some of this wasn't clear

number number times two this is just a

fancy way of writing function that takes

in a number

and then you go return number times two

so you're you're creating a function on

the fly here okay you're creating like

an anonymous function with no name on

the fly here

and or lambda function and you're just

passing it that function okay this is

what's called a higher order function

you're passing it a function this right

here is a function like this right here

is a function

this right here

uh right here is a function

and so we're gonna create a function

here

function

and um

let's let's give this a try okay so

what does reduce do

reduce loops

and gives you back the accumulator

all right so

this is going to be my previous value

this is going to be my next value i'm

just going to call it any x for now and

let's just go ahead and console.log

previous and next

okay and let's run this and let's see

what happens

okay boom i got one two

so what's previous and next in this case

right this is our accumulator so it's

it's basically going to be like this is

the previous value this is the next

value so if you do previous plus next

it's going to do one plus two

and then

previous is going to become three

okay preview is gonna become three

all right and then you're gonna go

through this

and do three plus three and you're gonna

turn it into six

now what i'm gonna do is i'm just going

to go

return

previous plus

next okay or previous plus

current that's usually what they call it

okay current so let's do previous plus

current

and

i'm going gonna store the result of this

in results so let's go const result is

equal to that

and we're gonna go console.log and let's

get the result and let's take a look at

what it is and boom you see that we just

got back six okay so

this function here with the result um

with

using reduce it made our life really

easy right being able to go through this

entire thing and sum it so quickly with

essentially one line of code that's a

total game changer now let's see if we

can even make it simpler so we're going

to use es6 notation and turn this

function here into an es6 function so

watch what happens so this function part

is going to lose this right here and we

don't need that we don't just say

function anymore we're going to put a

greater than

equal and

equal and a greater than sign and then

this part here we we want to do implicit

return so we're going to remove the

return but in order to have implicit

return you also need to remove this

squiggly like curly braces we're going

to remove them

we're going to format it okay

and you can even if you want try to get

this on

one line

so now that entire solution is just one

line

so you're using reduce

and you're summing up all these numbers

so when i hit run watch what happens i

got a six

and guess what

can you remember where we've made a

function that takes two numbers and

returns their sum because that's all

you're doing here you're creating an

anonymous function

that takes in a number

and then just returns

and just sums both of them right that's

all this is doing so can you remember

where we've created a function like this

okay i'll give you a couple of seconds

five four three two one to find it

and let's see if i can find it as well

so if you look

we created a long time ago

we created this function sum right here

okay and we even have its short version

right here some arrow two some arrow and

then we also have some

so let's see

if we can feed it that function okay so

now you're going to start to understand

why it's called a higher order function

so let's bring it down let's bring some

down so i'm going to copy this

and i'll bring it down just so you can

see it easily

and what i'm going to do here is instead

of even writing all of this first we're

going to turn it into one line of code

how we had earlier so we've done that

right

we said

previous current

right and then return previous plus

current so sum up those two numbers we

could also say a comma b

return

this so if i run this this should still

give me a six as expected

and here's the cool part i can actually

just feed it that entire function just

like this so i can just say hey

reduce it to one number

and then just

sum it so that's why it's called reduce

because it's an array and you're

reducing it down to just one number

right it's gonna return one number here

that's why it's called reduce and then

i'm giving it the sum function and what

the sum function does

is

it just takes in

things and it sums them up so let's run

this and this still gives me a six let's

say i wanted to multi take the

multiplicative product of all of these

numbers right so i would want to do 1

times 2 times 3 times 4. what would i

need to do in order to get 1 times 2

times 3 times 4. see if you can do that

with reduce okay so take a few minutes

and try it on your own i'll give you

five seconds five four three two one all

right let's get let's go all you would

have to do is you just have to copy this

create a new function call it multiply

and you just change this a plus b to a

times b

and just feed it multiply

and now it'll just keep going through

multiplying those number saving their

accumulator and spit it out so

you feed it

sum you get some you feed it multiply

you get the multiplication

multiplicative

product at the end

so anytime you're

using reduce you could create your own

function or just on the fly just go a

comma b

a plus b this is a pattern i use very

very very very very often

and i hope that you use this don't

anytime you're thinking some just copy

this for now literally you can copy and

paste this most of the times whenever

you think some this is usually going to

be the answer and then you know you can

stack overflow it later and just go hey

how do i sum up something with reduce

how do i do this with reduce and you're

going to start

learning this reduces something pretty

complicated and so i don't want you to

go fully down the rabbit hole but just

learn it with pattern recognition

anytime you have to sum up numbers use

this right a good exercise for you to

try would be

how can you use reduce to sum up all of

these net worths okay so get the total

net words so try giving that a you know

see if you can give that a try i'll give

you five seconds and then we'll try to

solve that together okay so i'll give

five

four

three two

one

all right let's try to solve that one

together all right so i got all these

net words over here

and i want to sum them up how do i do

that by the way just a pro tip in

replied there's something really sick

that allows you to explain code so let's

say you're not understanding what this

is you can highlight this right click

and click this button that says explain

code and this does a pretty freaking

good job this code takes the array nums

and reduces it to a single value by

adding each value together

that is a really good explanation so you

could hit yes and then you can also hit

regenerate and it generates a new

explanation for you so this code takes

an array reduce it to single number

adding all the numbers together

so

that's a really freaking awesome feature

of replica make sure to keep using that

anywhere you're kind of confused and you

don't know why we're doing a certain

thing i mean i'm kind of blown away by

it it's really it's really good okay so

like for example look at line 356 right

now right

if you highlight this and right click

and hit explain code

it will tell you watch this code is an

example of template literals

brilliant it is used to display the

value of variable called names inside an

h1 tag

this is brilliant this is explaining it

better than me let's see what it says

about this filter one let's see how good

of a job it does here so let's explain

code

this code filters the actors array for

all actors that have a net worth greater

than 10. oh my god

oh my god

so now let's play with this um actors

array that we were working with earlier

right so i'm going to comment out all of

this stuff here for a second

and i'm going to go back to this actor

stuff and let's go ahead and we don't

need to uncomment anything let's just go

down here and i'm just going to say

actors.reduce

and i'm just going to write what i had

written before and then i'll then i'll

start using my brain okay and so there's

gonna be an accumulator oh one of the

things

that is kind of useful to know that i'll

kind of tell you in a second

is this okay let me actually tell it to

you right now so you're not confused

later okay so let's go ahead and comment

all of this

right here

you could pass in so it this reduce

takes in two arguments one argument is a

function and the other argument it takes

in is like some kind of number okay so

it takes in two arguments

so we have already given it a function

and then we can give it another argument

like a zero so watch what happens when i

run it right now i get 10

but i could also start the accumulator

from negative 10

and then it will count up to zero right

or i could start it at already ten and

when i started from there it will count

up to twenty so this secondary argument

by default usually it starts at zero but

you can also specify this one so helpful

for you to know if you don't need that

you could just write it like this okay

but i'll just leave that here so you

know

that there's different options for you

available okay let's go back to this

part here where we were writing actors

reduce so this is going to be my

previous value okay and my accumulator

is going to be zero and then what i'm

going to do is

for my current value okay so this is

previous this is current and i can just

say dot net worth

and let's see if this does what we want

it to do let's console log the result of

this

and if it doesn't then we'll try to fix

it and looks like it does it combines

all of those net words already okay so

this is previous

right if i had to write it in a verbose

way

let's write here previous

this is current

as you just say current not net worth

and then previous is that so previous is

like in the start previous is zero

then previous is like

uh whatever the result of this was

so it's kind of like recursive

why is it yeah so okay so think about it

like this right we're going through it

the first time

first loop first

previous is zero so zero plus 20 million

or whatever is 20 million so then

previous becomes this next time then 20

million plus 10

then that becomes you know that like 20

million 10 or something like that right

and then

uh you add it again and then previous

becomes the sum of

20 million plus 170 million so this

becomes like

190 million or something like that okay

and so that's how previous works do this

we'll say console.log

and i'll run this and if you remove the

zero this should still work because by

default it's uh zero oh no actually in

this case it won't work c so we have to

actually pass in a zero so that's why

that's important uh because something

because it was trying to like add the

objects on top of each other so it

becomes weird so just pass in that zero

if you need to and then this way you can

sum it up so see reduce allows you a

nice little way to sum up this whole

thing

let's comment this out all right let's

run and hopefully nothing prints out

beautiful so just to recap we talked

about

map function and how you can use map to

double numbers

we talked about filter and how you could

filter for specific net worths we talked

about

reduce

and how you could reduce things to a

single value and sum them up together or

essentially how you could sum up things

without having to

you know loop through and do it all

manually reduce allows you to do it kind

of in one go so you know and we talked

about higher order functions how higher

order functions

work together meaning it's a function

that takes in another function as an

argument that's why it's called a higher

order function so we talked about those

there's a lot that we covered and this

is kind of like the part where it gets

kind of complex and it's like what is

happening things will keep getting

harder so i don't want to promise you

things will get easier but this is one

of the pretty challenging parts to

understand if you don't really grasp it

right away don't beat yourself up it's

totally normal it's okay all right

you're in the right place

with that said we're going to keep on

rocking and rolling and learning new

things

all right boys and girls let's get back

to it before we're very close to getting

to that rock paper scissors game for you

and that's going to be really exciting

but first things first

we have to work on

getting your

dom skills up okay so let's go ahead and

talk about

dom manipulation and no i'm not talking

about a dominatrix get your head out of

the gutter okay i'm talking about

this dom right over here all right so

when you see stuff in this console log

right here

that usually has to do with

um

that's just whatever is in your console

but when you see stuff here that's your

dom okay it stands for

document object model which

you never have to remember again okay

it's just like nerdy knowledge that

won't really be super useful for you in

the real world you'll just refer to it

as dom most of the times dom and it's

just hey this is the stuff that's

showing up here okay so how do i change

this exercise to say

exercise how do i say change

this projects here from being

written in black to be written in red

all right all of that requires you to

manipulate the dom

when we're playing rock paper scissors

right how come when i

click this button watch

it's going to say rock versus scissors

you win when i click this hand

let me move myself here when i click

this hand watch what happens

boom boom boom boom boom boom boom boom

right all of this right here my friend

is just dom manipulation boom dom

manipulation

this changing here when i hit this red

button right here watch what's gonna

happen boom everything got cleared up

that right there dom manipulation

okay so let's go back

so that's what we're gonna work on okay

how do we actually make stuff happen on

the screen how do we change stuff on the

screen with javascript how do we mess

around with the html

with javascript

and we're going to play around with that

a little bit

so let's go ahead to our index.html and

i'm going to go ahead and add in a div

okay and

we can add in a div

actually let's do this to do some dom

manipulation some of this stuff let's do

it

also outside of this replace stuff that

we're doing here so you can start to

learn how to do things from scratch

yourself as well okay so just do me a

favor hit command t or control t on your

computer open a new tab and let's go to

replic.com

okay

and now here just open a new repl

okay so for example there's a multiple

repels let's go back

multiple rebels that show up here let's

just choose the html css and javascript

one okay depending on when you're

watching this maybe if they updated the

site click a plus button and then choose

html css and javascript okay whichever

way you want to do this so i'll just

click here

and what do we want to call this i'm

just going to say dom manipulation

lesson

all right

and then go ahead hit create

perfect it'll bring you to here

okay and if you hit run

uh right now you should see hello world

on the screen how are you seeing this so

you came with three files here

index.html script.js style.css now to

style.css don't worry about it just for

styling

the main ones that we're going to be

worrying about here is the html and the

script

so

this is pretty much standard html that

when you just like make any javascript

app

you you you know you you kind of start

off with but to make it even less

intimidating for you to start off let's

just remove almost everything we're just

going to leave a script tag here

and let's say if we can say hello world

in this h2 and let's hit run let's see

if this works so it looks like hello

world shows up here so this is literally

two lines of code okay

and let's even write this line of code

here so you understand how to link a

style sheet to your javascript sheet

okay so hello world

and

now let's go to our script.js file and

we'll write console.log

and i'll say hello and i'll hit run and

notice the problem that we ran into

right

where is our hello hello why isn't this

showing up in the console what we need

to do is link this style sheet

to this script sheet okay so we need to

go ahead and do that let me zoom in

a little bit so you can see everything a

lot more clearly so let's go ahead and

do that and i'm going to link this

okay move this over here

so we're going to say script hit tab

and it'll create these

tabs for you right

and then we're going to say script

source is and for source i'm going to

say script.js because this is the name

of this file

you could call this whatever you want as

long as you change the name here for

script

let's hit run

and

[Music]

now you see hello over here is showing

up

okay

perfect

so we have linked our index.html with

our

script.js

okay now let's do basic dom manipulation

okay how are we going to do this well

what i want to do is this h2 i'm going

to give it an id and we're just going to

call it title and then we're going to

come here and i'm going to say let

title

equal

and

what's cool about javascript is you can

do something called

document.getelementbyid

so we're gonna pull

this specific element right over here

this h2 right here by putting in the id

so what's the id

can you guess

right it's title

okay

so i'm gonna get this id and then let's

go ahead and console.log this and let's

see what it shows us on the screen so

i'm gonna say console.log.title

let's run this

um sometimes if your app kind of breaks

out like this just hit

just go ahead and hit refresh so i'm

going to refresh here not a big problem

all right let's run it again

and you can see that it says hello and

then it says html heading element so

it's it's showing us something that's a

really good sign now what i want to do

is i'm going to say take the title

okay and we're going to see if we can

grab its title dot inner text so let's

try this let's see if we can do this

ah so i'm actually able to pull the text

of this title so now let's go to our

html and change this hello world to

hello world

hello

knight

and let's run

and and you can see that we're actually

pulling hello knight from here

right from html

we're pulling that and reading it in our

javascript so that's a really good

sign means

we can actually now do stuff with it now

here's the cool part how can we go the

other way how can we update our html

from our javascript and then it'll show

up here so let's go ahead and do that

now i'm going to say title dot inner

text

and let's just change it to whatever we

want okay so let's say we want our inner

text to say

goodbye

so let's say we wanted to say goodbye

my lover

goodbye my lover goodbye my friend you

have been the one

there we go so look at that right now

i'm gonna i'm gonna let's um

let's run this

and you see for a fraction of a second

it'll say hello

night and then it says goodbye my lover

so let's run this

fraction of a second and then it goes to

go down my lover

so

we're printing out the text before

changing it let's also print it out

after changing it so we're gonna say

okay and in our console log here

we're gonna say before

like that and then here we'll say after

like that

and

let's run this now and you can see

before it was hello at night and then

after it became good by my lover so that

is

the heart and soul of dom manipulation

okay this is this is what it is now if

you want to change the html you can do

that as well so watch this i can

actually go ahead and do

title.inner html so i can actually

change its html

okay so

it was an h2 right i could actually say

put it in p tags

and change it so let's say

we'll make a message so we'll say co let

message

equal and here i'll put goodbye my lover

that'll be the message and then we'll

say it's whatever the message is right

boom

so

let's comment out this last line right

now and let's go ahead and run this and

watch what happens

okay so i should get pretty much the

same exact thing all i've done is create

a variable message putting it in here

now watch what i can do

i can put that same message within these

p tags okay so first let's just start

off by doing hello just so we can get a

sense of how this is working

and you can see that we've changed our

inner html to this all right so notice

the problem we're running into right

when i do p tags it's still showing

title tags it's because it's inner html

okay so if i go back to this tag here

this doesn't have any other inner

elements

if it had other inner elements it'd be

able to change them

so there's nothing for it to change here

okay so here's what we want to do

instead

we want to actually wrap this entire h2

in a div

all right so let's go ahead and copy

pick um cut that paste it here so now

here's what it should look like

you should have one div

and that div should have a h2 inside of

it that's it okay one last thing we need

to do is we need to give the id not to

the h2

but instead we need to give the id to

the div okay so the div should have the

id not the h2 let's go ahead and try

again so now i'm grabbing this one when

i say get me

um when i said get me title

it's getting me this div right over here

and then when i say change the inner

html it changes this

and to be even more clear what i can

right click and rename all occurrences

and we can call it title div

okay so what i'm doing is i'm grabbing

the title div and then changing its

inner text and its inner html so let's

go ahead and give that a try now

and you can see that i get back hello

now in order to make this hello instead

of hello this message show up that we

wrote remember let's use template

literal so see if you could replace this

hard-coded hello with this message right

over here so take five seconds okay

it'll be a good practice and using

template literals remember to start with

backticks

and uh pause the video try to yourself

five four three two one and let's go

ahead and do this now so i'm gonna

replace this with backticks

back text right here okay and then

this here is gonna become a javascript

variable so we're gonna go like that and

i'm just gonna put message in here okay

let's run it now and you can see it says

goodbye my lover and then there are

other things i can do as well right so

for example i can actually grab this div

right here and change its style property

and make it red or green or blue or

whatever i want here's how we can do

that let's go ahead and do that from raw

html file and here for this div i'm just

gonna pass in a style attribute i'm

gonna say style and we're going to put a

string here and i'm going to say color

make the color blue so let's run this

color is blue and put a semicolon here

and run it don't put blue as a string

because it's already a string

and there we go goodbye my lover okay if

i wanted this to be the background

change the background color instead

this is how i could do it

there we go so we could do background

color like this okay so let's go back

to how we had this right here

okay so now in order to do that i'm

going to remove this entire thing let's

do it from our javascript file instead

so i'll go to my script.js and if you

want to move around in a really

comfortable way you could actually do

command p and then do script.js and

command p

so this allows you to kind of move

through without even having to use this

um you know navigate through files like

that

so here i'm going to do title div dot

style dot color okay and this actually

will get me the

uh color property

of uh that div okay whatever color it is

or whatever and what i can do is change

it so watch this actually

so i could say color and let's go red

let's run this and i just made the color

of this div red okay

now another thing i could do is i could

change the background color and how we

could do that it says we could we can't

put

dashes inside of a variable name

i could do background color like this

and then we could hit run

and now it changes the background color

of it to red

okay so there's a lot of stuff that we

could actually do

but i think the few key things that i

want to show you more is actually like

on click all right and how that works so

that's going to be another really

important one and you're definitely

going to need to know that for

tic tac to uh sorry rock paper scissors

so let's make sure we have

we have this figured out

in order to do to to do this exercise

i want to give you context so here's the

context

in our rock paper scissors when you go

here

okay

and you run this

app

okay let's go ahead and open this up

actually in its own browser

let's go right here rock paper scissors

right watch what happens

when i click here it detects that i've

actually clicked rock

when i click here it detects that i've

actually clicked a hand and when i click

here it can actually detect that i've

clicked

scissors

so we're going to

do like a baby exercise that's gonna

highlight this okay so we're gonna make

a

we're gonna make three squares

and each square is gonna have a

different color

all right so we're gonna have a

red square a green square okay a green

square and a yellow

square

okay you could do it in whichever order

and what we would want to do is when the

user clicks

when the user clicks on one of these

squares

we just want to console.log

that property value so we want to read

it we want to be able to we want we want

it to say in the console log red

right when we click yellow it should say

yellow at the bottom right when we click

green it should say green at the bottom

it should be able to detect

which square the user clicked on and be

able to pull out that square's value so

this is going to be an important

exercise because once you can do this

you'll be able to attach and do more

functionality with the rock paper

scissors button because remember when

you click this a bunch of stuff happens

but in order to make that stuff happen

you first need to detect

that a button was clicked and you have

to detect which button was clicked was

it the rock one was it the paper one or

was it the scissors one so let's go

ahead and do this

uh red yellow green exercise

so in order to do this we're gonna go

back to our exercise page that we had

open

on this exercise we're gonna go to our

index.html and we're gonna make three

dips let's go div one

we're gonna make a div

two and we're gonna make div three

and this is going to have an id of red

this is going to have an id of

green

or sorry yellow yellow

and this is going to have an id of

green

now we want to give this a width and a

height

okay so we want to give each of these

with uh divs a width and a height so for

width

we'll say 100 for height we'll say 100

and then we want to give it a color and

so overall says style and we'll say

color is

red okay because this is a red one

and put a semicolon here and let's run

this and let's see if something happens

okay

so nothing has happened yet all right so

now let's make this red square over here

okay how are we going to do this so if i

hit refresh obviously that shouldn't be

there

i just made it to show you that it works

so let's go ahead and style this so what

are we going to do so i'm going to

create a style tag

and then we're going to give it a height

of 100 pixels

put a semicolon here we're going to give

it a width

of 100 pixels semicolon there and we're

going to give it a

background color

of

red i don't need to put a string here

because it's all a string

let's run this

and we have our red square so i'm just

going to copy this

paste it over this and paste it over

this so now i should have three red

squares when i run it

okay perfect now of course we're just

going to make it called yellow this one

we're going to make it green

okay and id and then we also need to

make the color yellow

and then we need to make the background

color green here

let's run

and you can see i have these three

squares

now what we want to do is we want these

to show up side by side instead of up

and down like this so this is a little

bit of styling stuff but we're going to

be really gross and we're going to style

everything in line styling

don't ever style like this okay but just

for now we're just going to style like

this so let's put all of these three

boxes inside of another big box okay so

let's put them inside of a container so

just wrap all three of those

um let's see if i could show it to you

in a clear way

cool

so

here you have your red div here you have

your yellow div here you have a green

div right

we're gonna put all three of those like

boxes that you created inside of this

big div right here

and then we're gonna style this one and

we're gonna say display

flex

run it

and now it should show it to put it put

it in a flexbox or show it to you like

this okay now what i want you to do is

when i click this red one it should say

red when i click this yellow one it

should say yellow and i click this green

one it should say green so let's work on

that now how are we going to do this

so here's the cool thing so first let's

go ahead

let's go ahead and grab our divs so this

we're going to need this red div we're

going to need this yellow and this green

so what i'm going to do here

is see if you can do this

document.getelementbyid

and

use this technique here to get the red

div okay i'll give you five seconds here

five

four three two one okay let's do it

together now so i'm going to say a red

div or let's say cons red div

actually let's say let because we might

change this later

red div is

we're going to do

document.getelementbyid so let's go

document.getelement

by id

and we're going to pass in red here

let's copy this and paste and paste

and if you're new don't copy and paste

just write it all down because it's

going to build your pattern recognition

all right

so i'm going to grab yellow here paste

it here green here paste it here so now

we have we're grabbing the red div the

yellow div and the green div

okay and here's what we're gonna do

there's something called dot on click

okay so i'll show that to you right now

so let's go

red

red div dot on click okay so this will

detect any event that's happening when a

user clicks

and we're going to set this equal to and

we're going to create an anonymous

function here

and we're just going to say console log

and in this console log we're just going

to say console.log you clicked red you

clicked red because we already know the

click read right because we've grabbed

this entire red div

we grabbed this entire red div here and

we stored it in this variable right

there

okay so let's hit run

and let's click red and it says you

click red okay

and now we can just we've been removed

you clicked and so when i click it it

should say red

now watch what happens when i click

yellow nothing happens right when i

click green nothing happens so red knows

its own bounds and it can detect when

it's being clicked on thanks to this dot

on click

and then we just pass this anonymous

function and then we can do stuff here

right so

if you wanted to be able to write

multiple lines of code here you could do

this

you know console log red say

hi whatever right so then you could run

multiple lines of code like this and you

could run them

so that says read high every single time

i click this

the other way of writing this here

that we're writing the short that we're

writing here the other way of writing

this would be to say

give me a function here

with no arguments and then that just

console logs it says red

okay so that would be another way of

doing this so when i click red now it

still says red okay this is kind of like

the old school way of writing functions

and you could still do that

but arrow functions are

just make things look cleaner

there we go

try see if you can try to do the same

thing for yellow div so when i click

yellow

it detects that i'm clicking yellow and

see if you can do the same thing for

green so when i click green it detects

that i'm clicking green i'll give you

five seconds

five

four

three

two

one

all right let's try it together so you

know try pausing the video if you want

to try it yourself or let's go ahead and

do it together now so i'm just gonna

go copy here paste paste

and then this red i'm gonna change it

with yellow and then i'm gonna copy that

yellow right there and paste it here and

this red here i'm gonna change it with

green

and i'm going to copy that green and

paste it here

okay so let's try running this and watch

what happens so let's go run this now

when i click red it detects red

beautiful when i click yellow it detects

yellow and look at how sensitive is

right

even when i click right

right here so close it detects it like

look at that

when i click when i move just a little

bit over it detects red when i move just

a little bit over it detects the yellow

so it's really good and now let's try

green that's what we want okay because

what what you guys are gonna do is

imagine instead of red this was a rock

so what you're gonna say is

well

you know

let's say

uh

you say

user

chose

rock

okay so that so when you click red let's

run this first you click red it says

user chose rock

and then maybe

what happens next is you calculate

um

you know random

you get random computer choice

so maybe random computer choice says the

computer selected

you know maybe paper okay and then what

do you do you compare these two against

each other so you compare user

choice uh versus

computer choice um and then you figure

out a player choice versus computer

choice and then you figure out like

which one is better so then you put them

against each other and you

you find out like what the result is

right

maybe

you know if you lost you should get

negative one if it was a draw you get a

zero or you get a one if you won

and then you show all of those on the

screen so you know it shows the results

on the screen like it says you win but

on the dom right on the dom so another

order of saying screen is really just

dom so then it shows it on the dom

document object model where the users

can see it so that's that's really like

the bare bones of how you're gonna start

being able to do rock paper scissors

okay so you really need to understand

document object model

and how dom manipulation works is the

most basic version of it but honestly

this is really all you need and you'd be

able to do that rock paper scissors

uh no problem

so hopefully you enjoyed learning about

dom

and with that said we're now going to go

ahead and start covering more stuff

let's actually do one additional

exercise on this because as you've

noticed

you had you had multiple things

and you wrote

the same code but multiple times here

you know pretty much the same code

multiple times here so one way i want to

show you is you actually could even like

loop through all of these okay and then

actually like

kind of

you know do the thing that you want to

do with them all at once so i'll show

you now

so what i could do is um

at this level

let's go ahead and give a

class to all of these so i'm going to

basically say

class is

color button

all right and let's end the quote and

let's do that for all of the buttons i'm

going to go here

and we're going to give it a class

oh sorry let's copy this let's paste it

and let's go ahead and do it here as

well okay so now what you should have is

three like squares or whatever right

and uh the class is just color

you could call it color square

that probably is a better class name so

color square color square color square

okay now if we want to get

all of these elements all at once what i

can actually do is i can say console.

actually let's do it like this i say con

squares and i can say get

sorry document

dot

get

query selector

all

and then i can pass in the class that

i'm actually looking for so in this case

i'm looking for the class

color

square

let's also

console log this and let's run it all

right and i get back a node list so

that's exactly what i was looking for

okay now let's see if i can loop through

these

before we loop actually what we need to

do is let's run this

and node lists right now is empty so

that's not what we want we want to put a

period here period color square

basically says hey i want to look for

the class them color square okay so this

is classes

and i'm going to select all the classes

i'm going to return them to you as like

an array or a node list

perfect so now i have all these elements

right over here all right so let's just

make sure we're getting all of our color

squares and console log this one is

console log

squares let's run this

and boom you can see we're getting

all of our squares right here because

we're getting three html developments

perfect

now here's what one thing we want to do

okay

in order to do this go ahead and change

all these two buttons because in rock

paper scissors you're not gonna these

aren't gonna be divs these are gonna be

butt tens

okay because if i go to here these are

buttons okay these are buttons buttons

buttons

cool

so let's go back here and we're going to

change these divs to buttons so button

end it with the button this is going to

be

a button as well

button here and button there

cool so now that this one div here

has three buttons

perfect

so let's hit run and let's make sure

everything is working as expected red

red red yellow yellow green green green

perfect

now what we're going to do is we're

going to give each of these buttons a

value okay so we're going to give this

button a

value of red

we're going to give this button a value

of yellow we're going to give this

button a value

of green

and let's go here and we're going to now

say now that we're getting back our

squares let's go console.log square

let's grab the zero square and let's do

value

okay now when i run this code you're

going to notice

oops square is not defined ah squares of

zero dot value let's do that

okay and let's uh let's comment this out

so we don't have to worry about this

anymore comment this out

and you can see we're extracting the

value here and we're getting back red

okay so that's a really good sign

now if i do this again

i'm going to get back

yellow but if i do this again i'm going

to get back a 2.

so instead of repeating this code again

and again here's a great point to write

uh

what do we write when we have to repeat

a ton of code over and over and over and

over and over and over again

we use a loop and specifically let's use

a for loop and let's use it for each

loop okay so we're going to say

and for each is one of the best loops so

if i haven't shown you that

up until now i'm going to show it to you

now okay so four each is my favorite

that one is even better than a um

four of loop okay so let's go ahead and

use a for each loop so i'm going to say

grab squares and then for each square

okay let's just console log so grab each

for each square

i'm going to console.log square.value

let's run this

and now you can see and we're going to

comment this out and let's run

and you can see i get red yellow green

okay

now what i can do is i can loop through

this

and basically make this function right

over here multiple times okay so i can

actually say

hey

for each square what i want you to do is

actually update its on click property

and set it to this function so now we

can actually just go ahead and do that

so i can say square dot unclick

and we're going to set that to

console.log

that square's

name okay and we're gonna take all three

of these lines and actually comment them

out because we don't need them anymore

so let's go ahead and run

and check it out

red red red yellow yellow yellow green

green green whoops we're getting some

weird error let's run it again

oh because that name is not a thing i'm

sorry let's do dot value let's run it

again

and value is being pulled from this html

attribute that we created right here

value that's where it's coming from so

let's go back let's hit run

click red yellow green yellow green red

right so look at how nice this became

now we don't even need

this big chunk of code anymore

right we just

have this here

okay so let's i'll leave the comments

there for you let's run

click click click click click click

click click click right so this is super

nice and uh this pattern you're

definitely gonna need it for when we're

making our rock paper scissors game so

keep this pattern in mind this is an

example you're gonna be definitely using

all right let's um

dude times clicked okay so let's take

our app um

up by one level so this dom

red yellow green squares app that we

made okay so i'm going to click on this

here

all right

and um and we're going to take it up up

a notch so we want it to be where when i

click it it actually says the number of

the times clicked here zero if i click

red one it should give me one if i click

yellow four times it should give me four

here and if i click green three it gives

me three so how are we gonna do that

we're gonna start combining a lot of the

things that we were learning okay so see

if you could attempt it

but let's do this together so you can

just get some more practice here so i'm

going to create a object called times

clicked it's going to keep in store how

many times any of these colors is

clicked so we're going to have red

is clicked

uh red just click zero times

we'll have

yellow

zero times because start off everything

is zero right green

is going to be

zero

we just have it like this for now

and then what i'm going to do is just on

click here

i'm going to turn this into a full on

full function yeah like a function but

not just that returns right away

so we can write stuff here

i'll comment out the square value part

for now

and what i'm going to basically say here

is um

hey basically what i want you to do is

grab the times clicked object

and put this in as the key so

uh and and basically grab its key okay

and we're going to say dot value

so dot value will be whichever one i

click remember so the dot if i click

this the value is going to be red

and what i'm going to say is increment

that by 1. so if i click here

the value is going to be red

and then my object is going to go find

the key where it says red it's going to

find this

and then i'm going to say plus equals 1

its value so it's gonna increment this

by one

and uh we also want this to show up

like

here we want it to show up right

so now what i'm going to say is i'm

going to say

that square inner text

we're going to change it to

[Music]

times clicked

squared up value

all right so let's go ahead and run this

and i'll click this click red

boom

boom

boom

perfect

okay and if you want the most updated

version of this app i'm i'm imagining

you're coding it up in your own rupple

and that's great if you're coding it up

here in your own replit but if you want

to merge if you want to see the finished

version you know it's going to be in

here in this dom folder red yellow green

exercise

and then you just can come here this has

a solution there so you can just

navigate here pick the solution and then

see it okay this is the most updated one

this is the one i'm doing right now

and that's how it shows up and i click

here boom it shows up right so look at

that right how nice is that if i click

yellow 10 times it shows it to me click

read 10 times

whatever i'm doing it's it's keeping

track of everything so this is where it

it's

nice to work with objects and things of

that nature this is why we practice all

these things so now there's a lot that's

going on here

there's a loop going on there's an event

listener called on click happening

we're going into this times clicked

object and updating its key values and

then we are manipulating the dom and

showing that result

on here right so there's a lot going on

here and with just these few lines of

code

and so

you know it's a lot but that's why we

built it all up step by step so

hopefully you enjoyed this exercise

for you know furthering your dom

manipulation skills

now one thing one more thing i want to

show you here is how to clear this so

basically to start a new game because

for rock paper scissors you're gonna

need to know how to do that right so for

example we play a game we keep track of

the score right so that's why you need

to learn how to keep track of a score

and then when we hit this red

it ends the game

right so it clears the game and then you

start from scratch all over again so if

we go here we want to be able to add

that functionality so let's go ahead and

try to create this together okay so i'm

going to say const

clear

scores

okay or you could call it function as

well whatever is easier for you honestly

it doesn't really matter

and what clear scores is going to do

is it's going to take

you know all of these squares here

and it's basically just gonna clear up

their inner text

okay so i'm gonna say squares

dot for each square

i'm going to grab square.value

and we're just going to set that to

empty so we're just going to set it to

nothing so we're going to loop through

take each square set its value to empty

and then that's kind of it okay so this

is going to be my function that clears

everything so this looks good to me now

we just need to make a button that can

detect that that button is being clicked

okay so

we will go

here

in our index.html file alright and we

want to add in a button

that says clear game

or something like that so it's obvious

so if i go back

i see clear game button is right there

so perfect

oh sorry actually we're going to give

this button we need to give it a id or

something right so we can grab it so

let's call this clear clear dash game

that's fine let's go back into our that

script

and then i'm going to basically say

once clear game

div

is

do document dot get elements by id and

the id in this case is clear game so i

have my clear game div

and um what i'm going to say is clear

game div dot on click and i'm going to

set its on click to this function right

over here so i'm just going to clear

scores just basically when i click on

click

run this function right over here

okay so i'll put this function right

over here

and let's try it so basically right when

i click

when i click this

button

okay or maybe let's call the clear game

button

clear game button

let's do btn so our code looks

nice and clean on the same line

and now when i click clear game button

it should clear all the scores so let's

give that a try oh it's not doing that

so let's see if we can debug it and see

what's happening okay i'm trying to

change its value but instead of value

what i'm meaning to change is the inner

text so let's go enter text

and we're going to set this text to

zero and let's try now

let's run this

let's go back in the game

there we go

right there we go now

it's doing it correctly

clear game it starts from scratch

what happens if we set the text to empty

text so let's see what happens does this

give us an error no

so this this might actually be even

better just set it to an empty string

or a zero

and you're good to go here

so now this app is

really coming out nice right this app is

doing a really

really good job and

i mean yeah this is a great app looks

really really nice so there you go like

this here

should give you a very clear idea of dom

manipulation how to make things work

like if you have this example to work

off of i mean you're pretty set to go

with dom manipulation so great job if

you got this far nice work all right

you're making amazing progress so far

but here's what we're going to do now

we're going to step it up we're going to

go and start building a tip calculator

app so check it out i'm going to go over

here and we're going to do the following

i'm going to open this up so hit that

button right behind my face the top

right and it's going to open up this

this right here and we're going to go

over to tip calculator and hit click on

it okay

and here if you type in let's say

the bill total is a hundred dollars the

tip amount is ten percent and you can

see it already calculated it correctly

right because if the bill is a hundred

dollars and the tip is ten percent well

that's the tip would be ten dollars so

the total would be a hundred and ten

dollars per person but what if we had

more people what if we had two people so

watch what happens when i hit plus

boom the bill just got divided between

two people and so it automatically tells

hey john you need to pay 55 kazi you

need to pay 55 so both people know

exactly how much they need to pay what

if i keep increasing this number well

you see it keeps dividing

between all of those people so if the

bill was 110 dollars and you divide that

by 10 people you get 11 dollars per

person

now watch what happens if i keep

subtracting it's subtracting and

subtracting and subtracting it if i go

here and now subtract it watch it's not

gonna let me go down to zero right i'll

try a couple i'll try a couple more

times boom boom boom boom boom boom boom

boom nope does not let me go below one

so these are some of the functionalities

of this app that you'll have to keep in

mind so for example what will you need

to know how to do

well you'll actually need to be able to

get the user input

from this field right here

okay and this field let's say it's

called our this one over here let's just

say it's called bill total input okay

then you're going to have to get

data from this tip as well

and let's say this one is called tip

input okay

also you're going to be able to you're

going to need to be able to pull the

number of people at any given time

this one will probably be called let's

say number of people okay so maybe these

are all divs

or inputs that you can have you know

these are ids that you might be able to

have access to okay and then this over

here

this right over here

right this will be called per

person

total okay and all of these will be div

ids okay which means these are special

things inside of the html and you can

get access to all of this so then if you

want to get access to

this hundred and ten dollars you'll be

able to do something like per person

total

uh you know

div dot

inner text

or whatever right and that'll get you

access to what you're looking for

and that's just to show you how the

javascript portion will interface with

this app okay and then based on that

you're going to need to do things right

so for example you're going to need to

do some calculations that

you know maybe take the

bill

plus the tip

and then it divides that by the number

of people and then when you do that you

get this

so there's going to be a bunch of things

that you're going to need to understand

but take a screenshot of this actually

right now on your computer or with your

phone

because this will help you

constantly refer to certain key elements

on how this app is going to work

so i'm going to now explain and kind of

walk through this app and we're also

going to have you set it up on a new

repel so let's go ahead and do that now

so

this is going to be your tip calculator

exercise so how you're going to get

access to it so i'm going to zoom in

here so you can see everything

a lot more clearly

okay

and then we're going to kind of walk

through every single thing so on the

left hand side right you see projects

make click into projects all right now

when you click into projects you're

going to see

tip calculator so go ahead and click on

tip calculator and now you're going to

see exercise now don't go into the

solution because once again if i show

you how this works over here right let's

run this

and over here you'll see that we have

project exercises project solutions so

here's the tip calculator solution this

will be the fully working app so you'll

be able to type in 100 here and 10 and

it'll calculate everything correctly

you'll be able to hit plus minus minus

minus

so this right now is the working version

okay so if you need to see the solution

anytime don't go to it right now

do not do it but this is where the

solution will be and the main file that

you need to write code for is the

script.js file the javascript file

the index.html and the style files are

already completed for you so you don't

need to touch them if you make the

javascript work this entire app will

work okay so that's where your solution

is going to be but if you go to tip

calculator from project exercises and

you do

110

and

see nothing happens you can't change the

number of people it doesn't update your

score

there's no calculations being done here

so the javascript here is not working

okay so this is where your javascript is

not working

so

uh this is your exercise file okay now

what i recommend highly highly highly

highly recommend you don't just start

coding in this script.js what i

recommend is you create a new rupple

with these three files

right and then get started okay so let's

go ahead and do that now so i'm going to

create a new tab here

and we're going to go to replic.com all

right now we're going to choose html css

and javascript rupple and here i'm

basically going to say

let's go and say tip calculator exercise

and i will hit create rupple

okay now that this rupple is created

what i recommend you do is go back

go to your index

copy all of this so command a command c

or control a control c okay cop select

all right in here

copy it

go here and

delete everything in this index.html and

paste

what you just copied okay so once you

paste it you should see an ugly looking

bill

app okay

now the next thing we're gonna do is

we're gonna grab the style file so let's

go ahead and grab the style file copy it

come back go to your style.css delete

everything that's in here hit paste

hit run

and now the styling is complete so now

our app is looking good okay so this is

what style files stylesheet is for now

the last thing we're actually going to

do here

is

you see if you go to your script

there it's empty so we're going to go

ahead to our exercise

copy the whole thing okay command a

command c come over here paste it so now

when you look here

there isn't any real javascript code

written up okay and what i'm going to do

is i'm just going to collapse all of

these functions

and now what we're going to do is we're

actually just going to walk through

walk through like all of the um all of

the things that you need to know in the

gotchas right

and then you'll be able to just get

started and code it up yourself okay but

just let's walk through it together all

right so you're gonna be building the

tip calculator app now there are a

couple of things that you're gonna need

to know

all right otherwise this pro this

project is gonna become way harder for

you and i don't want that to happen okay

so i want it to be something that you're

able to kind of grasp

so there are a couple of functions

you're going to need to know their names

all right and you have access to them so

you have access to calculate bill

increase people decrease people these

are the functions you're going to create

these are the only three functions

you'll need and make sure to give them

this exact name they're already made for

you you cannot change their names if you

change their name your app will break

i'll explain why

these functions are hard coded inside of

our index.html okay so for example

when you are typing over here

typing over here every time you type on

key up

we're calling the calculate build

function

so that function is running literally

every single time you type here

that's why that function is there you

don't need to change that name the other

function i told you about for example

increase people and decrease people

function those are also written here

so for example you can see here increase

uh there's a plus sign

right there

right and then there is a minus sign

right there

and then there is a number right over

here

every single time you click this plus

button right over here

every time you click this plus button

this function increase people will run

every time you click this minus button

over here

this function decrease people will run

that's what's happening so that's why

these functions have special names do

not change them

unless you change them here and then

you're fine okay but i just don't want

you to

fall prey

the next thing

every time you

clickety clack and type anything in here

or here anything anything you type in

here here

you're gonna run this calculate bill

function

okay for your tip

um and your build total okay so

calculate bill

and then you also have calculate bill

twice you can see that

so this calculate bill is for this one

and this calculate bill here is for this

one okay so every time you type in any

of those fields calculate bill

automatically fires and runs

going um and then the other things

you'll need to know are a couple of

things like

you know

you have this bill input and you have a

tip input right so

you have ids like build total input

and you have other ids

like tip input so let's look for temp

input you have tip input okay now

because i'm nice

all right not everybody's gonna be this

nice but what i've done for you is i

have put it all into the javascript file

everything you need to know so you don't

have to go to your

index.html file pretty much at all okay

you don't have to like go and look at

anything

because what i've done here for you is

i've already just told you hey here are

the three functions you need to know

calculate bill increase people decrease

people

i'm already letting you know these

functions are hard coded in the html so

you cannot change their names

and then i'm already letting you know

these are all the div ids you're going

to need access to so you're going to

need access to build total input

this is going to be

this div or this input field

so that's going to be that input field

you're going to need tip input

okay this is going to be the user input

for tip

you're going to need access to

you're going to need access to so let's

just draw these again that's right there

tip input is right there you're gonna

need access to number of people which is

right there

this is a div okay so this is a div id

so once you get the div you're gonna

need to do dot inner text to get

to get these okay and then you're going

to need access to so you're going to

either for this i think you might need

to do dot value

one of those dot value or dot inner text

okay try both of them and it should work

one of them should work and then you

have per person total which is right

there

so those are the div ids you're going to

need access to i'm already telling you

their exact names so you don't have to

look in your html file

right over here on line 20 i'm telling

you hey get global access to all of

these inputs

okay meaning just get access to all of

these inputs right here before you start

creating your functions because your

functions are going to need access to

them

so

you know if i were you i'd do something

like const

let's say bill total input div or

something right and then or build total

input

and you can do something like document

dot

get element by id and then pass in bill

total input

okay this is just an example of how you

would get this specific one right over

here

all right so what i'd recommend is you

grab not just this one but all of them

so you have all four of these divs and

have access to them that's what i would

recommend you do here

going underneath here

i would i recommend that on line 24 line

25 get number of people from number of

people div

so once you get access

to these four divs bill input tip input

number of people div and per person

total div

you can use the number of people div and

from there you can actually get access

to the number of people by pulling the

dot text okay

and remember to type cast so anytime you

get a thing so let's say

thing

input and then you either do dot value

or dot inner text

but both of them are going to return to

you a string that's going to look like

this

and then you call the number function on

it and then that will turn it into an

actual 10 okay and then you'll be able

to do math on that because remember if

you take 10

string and you add another 10 string to

this

this is actually going to give you not

20

but

10 10 10

10 10 okay which is going to be silly

so

you want to do you want to do it the

right way okay so make sure you type

cast it use that number function

okay

so this is where you're gonna set up all

your globals and then you're gonna be

good to go now let's go into each of

these functions at a high level

so you're gonna create three functions

here

all right

and you're gonna define these three

functions so calculate bill

calculate bill will pretty much run

all the time like you should calculate

bill

when a user types it here automatically

you should calculate bill when the user

updates the tip you should calculate

bill when the user hits this plus sign

you should calculate the bill when the

user hits this minus sign

and ultimately what calculate bill is

doing is it's updating this number over

here the total per person owed

okay that's the ultimate job of

calculate bill okay you can see it says

calculate the total bill per person

that's what it does and then if you go

here there are ample ample ample amounts

of tips for you on how to actually do

this okay so i have tons of

notes for you

as you go and code this along so i hope

you don't have too much problems there

okay i'll guide you through everything

hey

get the user input and convert it into a

number so i'm reminding you to type cast

here

hey get the tip from user and convert it

into a percentage hey get the total tip

amount calculate the total amount and

then update it on the dom and show it to

the user right so updated on the dom

means update this right here

so calculate bill hopefully

that kind of makes sense at high level

increase people what this will do is

splits the bill between more people

all right

so what should happen here well it walks

you through it should increment the

amount of people

amount of i'll just say amount of people

then you update the dom with the new

number of people

all right so what does that mean

so you increment the amount of people

and then once you increment it you make

sure that you write that to the dom like

you change this one to a two for example

and this function runs increase people

increase people function runs every time

you hit this plus button so when you hit

this plus button

that function runs when you hit the

minus button

decrease people function runs okay

hopefully those are kind of

self-explanatory

uh but

hopefully that makes sense

and then at the end you want to

calculate the bill based on the number

of people so

i'm already giving you a hint you're

going to be reusing some of the

functions you've created previously okay

perfect so i'm going to close this

go here decrease people it splits the

build between fewer

people okay so there i'm gonna go over

the similarities between increase and

decrease people right if you look at

this

increment update the dom calculate the

bill

decrease people decrement

amount of people

update the dom with the new number of

people

and then calculate the bill based on the

new number of people so they're pretty

similar and how they work so once you

figure out one of them the next one will

be really easy

the only difference between decreased

people is you

when you hit plus you can go as high as

you want but when you hit minus you

shouldn't be able to go below one

because it wouldn't make sense right you

have the bill but then how come it has

zero people that owe it that doesn't

make sense so it shouldn't have zero or

you can't have negative people right so

you can't decrease the number of people

to zero or negative

so here i recommend you write a guard

clause i haven't shown you what a guard

clause is but basically it's just an if

here

it's a fancy name for just an if

statement and if statement is just

something along the lines of this okay

if something

something is not true i'm just going to

write it in english

just return

and what that basically means is this

will end the function so if you say

return

it just won't activate any lines that

are below it so let's say you were gonna

decrement the number decrement the

number of people here

but here you check for the condition is

people equal to one one or less you go

hey is people

less than or equal to one

if people is less than or equal to one

then don't run any of these lines of

code

right like just

stop the return here is just like hey

stop the function end it right here

okay and and you're not even giving it

anything to return just return stop

right here so that's an example of how

that would work okay so i'm gonna get

rid of all of that now

so that would be your decreased people

function

okay

so i hope that this exercise kind of

gives you everything you need to know

and now you should be able to get

started working on this project i wish

you the best of luck and

give it your best shot try as hard as

you possibly can i really believe you're

gonna make a lot of progress and i think

that if you really push yourself you

should be able to do this if you don't

get this done

don't get discouraged it's okay i'm

right here right we'll code this

together i'll show you the solution

next

um and yeah we'll just walk through this

together okay so pause the video now

give this a shot and try to nail this

and get this done and then what i

recommend is you come back and walk

through the solution because our

solutions might be different and you

might be able to pick up you know a lot

of things from how

maybe i solved the problem versus maybe

how you solve the problem okay and

remember in coding there always can be

multiple different ways and one way

isn't necessarily wrong okay it's kind

of an art form so we're gonna have

different ways where we get to something

so that's it um i hope you enjoyed this

and uh get to working and i'll see you

soon all right so i hope that you gave

it a try and if you got it good job for

solving the tip calculator if you didn't

it's okay we're gonna do it now let's do

it together so let's build a tip

calculator so here we're going to walk

through right and let's pay attention to

the instructions the first thing is

we're going to get access to all of our

inputs and divs okay so our bill input

tip input number of people div and per

person total diff so let's get access to

all of these now

so i'm basically going to say cons bill

input and we're going to say

document.getelementbyid

and we're going to say bill input total

build total input and then we're going

to get access to our tip input so we're

going to say

document.getelements by id

and i'm going to paste in tip input

because these are the specific ids i

need then let's get access to our number

of people div

and we're gonna do get element by id

and then we're gonna paste that in right

there number of people

and we're gonna do

get access to our per person total okay

and this will be per person total so

we're going to get access to all of this

and what global access means is because

we're defining it all the way up here

all of our functions will have access to

all of these divs

all right another thing we're going to

need is we're going to need the number

of people

from number of people div so now i'm

going to say let number be why i'm

saying let here is because the number of

people is going to change so sometimes

it's going to be 1 sometimes going to be

2 three four five

right so number of people is gonna

change so we're gonna say

let number of people equal

we're gonna go to our number of people

div

right and then we'll try and see if we

can do inner text and let's type cast it

into a number now let's see if any of

this works okay so in my calculate bill

i'm just going to try to do a console

log and i'm just going to say hey show

me number of people and let's just see

if like

any of this is even working right so if

i type in here

every time i

type it runs my calculate bill function

and every time it runs that it actually

shows me

my number of people

right

my number of people is one so that's why

i just keep saying one one one one one

okay now i can do console log and we can

also do bill input right and i can get

the bill input value and we can console

log that too so i can go here and say

one two three and you can see we got one

two three

at the bottom

right and the console log

abc and i got abc at the bottom

hopefully you can see that it's right

there

perfect so

it looks like i'm able to uh get

information from from these divs and

things so that's working so i'm going to

now remove these console logs because

i've verified what i needed to verify

now i'm just going to follow the

instructions that i have written here so

get bill

from user input and convert it into a

number

so i'm gonna basically say hey bill

input and

what i'm gonna say dot value should

honestly get me the actual

bill now i should just have to type

cassette to a number and this should get

get me the actual bill and now let's

just save it to a variable and we'll

call that bill let's console log bill

and uh let's see what happens okay so

let's run our app and one two three

right and our bill is

constantly being printed out to the

screen and it's a number so that's

that's good so i'm gonna remove this

console log don't need that anymore now

we're gonna get the tip from user and

convert it into a percentage so we're

going to say const tip

is equal to

we're going to do the same thing and

we're going to say tip input dot value

this time and we're going to actually

convert it into a percentage right

because that's what it says convert into

a percentage divided by 100 so we're

going to divide it by 100. now let's

console log the tip percentage

let's run this and i'm gonna do

10 and notice it gave me 0.1 because 10

divided by 100 is 0.1 so that's perfect

right we're getting our tip percentage

that means it's 10 great so i can get

rid of this console log don't need that

anymore all right now we're going to get

the total tip amount and how we're going

to get this is we're just basically

going to say you know it's going to be

bill multiplied by tip percentage right

so

now let's go ahead and console log this

and we're going to say tip amount tip

amount

okay and i'm going to just put it as an

object so it prints out kind of nicely

so let's go ahead and let's do

writing this is the same as writing this

both are the same so this is just like a

pro little pro hack all right so i'm

gonna say 10

and tip amounts did not get updated

interesting so let's go ahead and fix

that let's run this again let's say 10

oh because i'm not putting in a bill

total so let's go ahead and do 100 10 on

that tip amount is 10. uh what if it was

200.7 would be 20 dollars let's do 300

and you can see that tip amount is

calculating correctly right it says 30.

uh that's perfect so it looks like this

is working so i'm going to go ahead and

remove this console log don't need that

anymore all right now next up we need to

calculate the total so the total is

going to be tip amount plus bill so

let's go ahead and do const total and

we're going to say tip amount plus bill

okay let's go ahead and console.log that

now and let's run and when i type in 100

and i type in so uh 10

so right now tip is assuming zero

percent so now we have a hundred oh by

the way let's do that little trick we'll

do this

wrap it in an object let's try this

again and we're going to say 100 and

we're going to give a tip of 10 and you

can see total is 110. right let's give a

tip of 20

and total is 120.

so this is working exactly like how we

wanted to let's get rid of this now

now we're going to calculate the per

person total where we're going to divide

by the number of people

so that should be easy to do per person

total and we're gonna do total divided

by and we already have access to number

of people right here right this is

pulling number of people is pulling

straight from here okay so it's one and

we're type casting it into a number so

it's going to not be a string of 1 but

it's a actual number of one right so

we're going to do that divided by number

of people and now let's go ahead and

let's show that so we're going to do per

person total let's run this and we have

100

tip is 10

and per person total is 110. it's

because right now we're not able to

increase the

number of people right but let's say i

went to my html file and i just hard

coded that one to a two let's see what

happens i'm gonna hard code that to a

two let's run our app and let's see if

this works so i'm gonna say bill is

you know bill is 100 and then tip is 10

and you can see that it says 55 dollars

per person right which which makes ample

amount of cents 55 per person why

because it's 110 110 divided by two

people is 55. so now let's go and change

that hard-coded to back to a one let's

run our app again

and uh because we want to change that

dynamically right we don't want to like

hard code it in so make sure that this

is back to a one when you run your app

perfect so what's up next let's go down

and let's see what's up next and now

update the per person total on dom and

show it to user okay cool so let's go do

that

so i'm gonna grab per person

per person total div because i have

access to it from up here oh let's just

call it per person total diff okay so

per person total div we have access to

it up there let's p yeah per person

total div and we're going to change its

inner text to

uh per person total right over here okay

so i'm going to say per

person total

oh i'm sorry okay i'm uh yeah i'm just

kind of misunderstanding this but like

what i mean is

this is going to be total per person

okay

so that's

that's this div right here per person

total so we are updating it correctly

okay so let's just see what happens now

let's run this

let's go ahead and type in 100

let's type in 10 percent

and let's see what happens we're getting

back 110 so that's good but we want it

to be in dollars so let's go ahead and

do string template literals

and we're gonna

wrap it in this and just put

another dollar sign so

this dollar sign will just make sure

this is javascript and then this dollar

sign will actually put an actual dollar

sign so i'll say 100

and we'll do 10

and when we go here you can see that it

says 110

dollars okay

great

now what happens if we have a bill

that's something like this

148.5 what happens if we have a bill

that's like

decimals

you know or has maybe

weird decimals and now you can see

that it started showing like

lots of decimal places right like so for

135 dollars and 52 cents it says 149.00

like how are you going to pay that in

cents that doesn't really make sense so

what we want to do here is we want to do

a dot 2 fixed

so we're going to do that now so

you can actually

do dot to fix

two and pass in two right there and it's

gonna make sure that it doesn't go

beyond two decimals so let's try some

number again like that and you'll notice

that now it actually just goes to two

decimal places now what if the bill is

more like

3 000 or something like that it gives

you 3 300 but it doesn't you know it'd

be nicer if it kind of put a comma in

there right so if you want to kind of do

that what we can actually do and this is

a cool

uh trick that i learned that i use a lot

actually so that's why i kind of want to

show it off here you can do dot locale

string and just pass in um

en

us so it's just gonna

format it to us currency like a dollar

currency or whatever right and uh now if

you try

some bill

right you notice that it's actually

putting that

dollar sign and that comma or sorry not

the dollar sign but the comma which is

nice so like if you get some like i

don't know you're never going to have a

bill this much when you're eating food

right but all the commas are there and

if you get up to 25 million the commas

are still there so this is good now we

just want to make sure that we still do

that dot to fix thing so let's do two

fixed and pass it to two places right so

fix it to do decimals first and then

turn it into with commas let's try it so

let's try some big number

and let's do decimal places like crazy

and notice that the decimal places here

don't change okay

so great

all right in this case

all right lesson learned so it seems

like if you try to use dot two fixed and

locale string it doesn't work so just

pick one in this case we're just gonna

stick to dot to fix for now okay

so without making it much more complex

and that'll just take care of the

decimal places which is perfectly fine

actually but yeah our decimal places

will be fine

and then you can give whatever

percentage tip and everything will work

out as expected

so let's get rid of this console log we

don't need this anymore so i just got

rid of it

perfect so now it seems like our

calculate bill is doing

exactly what it needs to do write it it

calculates the bill in a really

intelligent way so now all we got to do

is increase and increase let's work on

increased people so here it says

increment the amount of people well i

already have number of people number of

people right here in line 29 so what i'm

going to do is i'm just going to copy

this

and paste it here and i'm just gonna do

plus equals one so we're just gonna

increment the number of people by one

and then we're gonna update it on the

dom

so we're gonna grab number of people

div which is gonna be

this div right here okay and we're just

going to pop in the number of people

that we now have so we're going to say

number of people

is equal to

number of people dot inner text

is equal to number of people okay

so now let's run this and let's hit plus

and you can see that every time i hit

plus it actually increments the number

of people and then it shows it and

that's why you can see that it's showing

it exactly how we want it to right and

right now minus doesn't work okay so

that's fine we'll do that in a second

but watch what happens when i do this

the bill doesn't calculate the right way

i have 10 people

okay so let's run this again

let's go a hundred dollars tip is ten

percent okay and let's run this

and you can see it's saying everybody

owes a hundred and ten dollars per

person that doesn't make sense because

110 dollars that's eleven hundred

dollars so how come the bill started

with 110 dollars and now we owe 100

110 or something's wrong so what we need

to do

is once we do this we need to

recalculate the bill based on the new

number of people which is super easy all

we have to do here is reuse the function

we just created so just call this

function and that should handle

everything so let's go ahead run this

i'm going to say we have a hundred

dollar bill i'm gonna say we're tipping

let's say 10

number of people is two and boom look at

that it's 55. why does it work because

remember

per person total is calculated total

divided by number of people so when you

update number of people here

this number of people updates and that's

the number of people

calculate bill function has access to so

when you run it again it just

recalculates this with a new number of

people after you change them pretty

beautiful right so very very simple

let's go ahead and do the same thing so

this code is going to be really really

really similar for decrease so decrement

the amount of people instead of plus one

we're gonna do minus one

number of people div we're gonna change

to update that and then we're gonna

recalculate the bill so it's gonna be

very similar to increase so watch what

happens when i have a hundred dollars i

have a ten percent tip i can go one way

and i can go backwards look at that how

nice but here is the problem i can go

more than i can go less than one watch i

went to negative one what is that i'm

going to negative numbers what is

happening how can i have so what the

restaurant now owes me for eating there

like they should you know what i mean

like the royalties there to eat

you are special you are a royalty so if

you went and the restaurant owed you

money i would understand okay fair

enough because you're here watching this

tutorial you're top of the food chain

all right while everybody struggles out

there you're here grinding it out so

then you can

level up your career provide for your

family provide for your kids you're a

champ tap yourself on the bat pat

yourself on the back do both tap and pat

do them both all right so we don't want

to go below one person so we're gonna

add what i call a guard clause here

basically going to say if

number of people is less than or equal

to one homie

just stop just stop

stop

don't run

this simply here means end the function

right here

and the decreased pupil function on line

70 and don't run any of this

so

let's try this again and i'll explain

110

now when i hit minus watch what happens

hit minus

nothing happens when i hit plus it works

when i hit minus it works but when i hit

minus now it doesn't work so what is

happening when it's one or less than one

it just says hey i noticed that this

function is running but i want you to

only run here and when this condition is

true because number of people is one

right just one less than or equal to one

yes it's true so then the code just

stops and doesn't end up running any of

this now in the other case scenario

where a number of people is let's say

two it goes as two less than or equal to

one and it goes false so then it doesn't

run this but it ends up running all of

these here okay so that's why it's a

guard clause right so we're just

guarding the entire code base and we

stop it okay to prove to you i'm just

going to say it's a long number of

people

so

i'm going to stop okay so let's go ahead

and uh run this and watch what happens

when i hit minus

it detects one is one or less than one

so i'm going to stop right when i go

here and try to run minus see it doesn't

happen it doesn't happen the console.log

statement doesn't happen doesn't happen

even here it doesn't happen even here

but when i go one more below boom one is

one or less than one so i'm gonna stop

one is one or less than one so i'm gonna

stop

so it's detecting it right every single

time every single time okay so we can

even like leave a little message for the

user and say you know

hey you can't

go you cannot less than one person

right so now like the user can see this

message and

no okay i can't do that right so

plus plus plus minus minus minus

hey you cannot have less than one person

and if you want to make it more

intrusive and more visible to the user

you can even do something like an alert

so now we go 100

10 percent tip plus plus plus minus

minus minus minus

says hey right

you cannot have less than one person so

this lets us know

right there that that's not a

possibility so you can do it whatever

way you want okay you could throw an

error if you want and like that'll kind

of crash the app and if you want to be

really pro i can give you one like kind

of pro javascript tip

is uh what you can do is you can throw

an error and show the user they're doing

something wrong but like kind of in a

sneaky way so here you can say you can

you can replace this

alert with something called a throw and

they'll throw an error so you do throw

and then what's nice about throw is you

won't even need that return like or just

leave the return here but like you won't

really need it okay so you can do that

return pattern i'm leaving this return

here to show you use a return pattern

again and again because that's normally

what i do but here if you want to throw

an error and really let the user know

you could do that right so for example

boom 100 10

i try to hit minus and it throws like a

red little error at the bottom says hey

you cannot have less than one person so

it's very clear that the user is trying

to do something that they're not allowed

to do and like you can make it visible

all right so there you go let's see if

this entire thing is working or not

let's open it up here and let's check

right

we just built this and we're excited

right

let's see if it works so we got a bill

we just went and ate at a nice

restaurant let's say you went to

cheesecake factory you took your family

out i mean it's a nice night out right

they gave you a big fat bill for 375

dollars maybe you maybe you brought some

friends with you and they're like hey

mandatory tip is 20 so you all start

freaking out who's gonna calculate it

what is it gonna be what's happening

right so you go okay we got the tip is

you know

10 or we're gonna give a 20 tip so

that's

oh that's 450

right now but you only have one you only

have selected as one person but luckily

you brought your friends with you right

you brought the entire gang hopefully

so you know you got

you got uh

juanes you got daniel you got frankie

you got lance you got nas

i mean you got the whole gang up in

there right so you got all these six

people

look at that

your bill is only 75 dollars

that's not too bad right that's not too

bad that's that's easy maybe maybe you

bring in two other people from somewhere

you go to them and you grab them and

you're like hey

come join our party and split the bill

with them too now the more the merrier

am i right you got 56.25

i mean this is at this point the

restaurant should be paying you right

this is nothing

cheesecake factory nice night out with

the family and friends i mean come on

that's a bargain

the 20 tip right

so this is this is really nice right

this is really nice app that we could

actually use and what's amazing is it's

already hosted online thanks to repple

yeah it's deployed on the interwebs so

you could put it on your portfolio you

could do whatever you want with it's

live ready to go

okay ignore that sound that was i'm

having a focus session and it makes this

little bang so now what i want you to do

is you're going to grab all of this

javascript code that you wrote

go back to this exercise

file okay

and go to tip calculator go to exercise

go to the script js okay

and then

delete everything that's in this

exercise file okay and then paste your

code in here

all right and give it a try and see if

it works so go and run it so go to your

now project exercises you should be able

to go to tip calculator

you should be able to

type in things like

100 10

plus plus plus plus minus minus minus it

should all

work smoothly okay so make sure you go

ahead and do that update your exercise

as exercise as you go so you have the

most up-to-date

version with all of your projects

completed all in one place nice and

ready for you to use

all right

that was the tip calculator i hope you

had fun i had a ton of fun actually

sharing it it's 11 53 p.m i was supposed

to have a date night with my girlfriend

we're gonna watch the boys the new

season of the boys is out i mean god

that show is good season three

started watching this indian movie

called rrr phenomenal

and um

about to move soon you know leaving

marina del rey man a lot's going on you

know a lot's going on

and instead of doing any of those things

you know i decided to be here and uh

build this app with you and do it

together so it's gonna be awesome

so i hope you enjoyed it i hope it was

awesome let's continue let's learn more

javascript i hope you're excited i love

your beautiful face and i'll see you

soon let's go

welcome back

now i want you to start getting ready

for rock paper scissors and by the way

just a sneak peek

you're going to be doing something with

netflix

soon so one of your projects is going to

be netflix okay so i hope you're excited

about that this is going to be with

vanilla javascript so this is just a

little sneak peek

now what we're going to be doing is i

want you to start getting ready for rock

paper scissors because we're about to

start building it soon but there are

just a few things that you need to

understand for this

all right so for rock paper scissors one

of the dom manipulation concepts

you're already good with like for

example when you click a button right so

for example if i go to rocket processor

solutions over here and when i click

this

to click and detect the button you've

already learned this concept so that's

good

um when i click the hand you've already

learned that concept so that's you're

good there

you learn the concept of being able to

hit this red button and then it clears

everything up right so dom manipulation

concepts you've learned so i'm happy

about that

i think the things that you still need

to know are how to select an item from

an array so let's go ahead and just do a

practice exercise together so remember

you're going to be coding in your

playground.js and i'm going to be coding

in just playground.js okay so this one

is for muah qazi

this other one is for you okay so this

one is going to be with all the finish

titles so

how do you select an um item out of an

array so let's practice that so here

let's say we create a new variable

called uh fruits okay i'll just do let

fruits

and let's see

did we make it earlier yes we did okay

so

i don't have to i'll just change this to

a let

okay

i'll bring this down

[Music]

you have to paste the whole thing in

we'll just do this

and i'll do it up until here

okay so fruits is only going to be

a couple of items

now let's go ahead and make sure that

fruits is we're able to console it so

i'm going to say console.log

fruits of

zero let's run this

okay one second it says it's already

been declared so maybe i don't need to

even say let here let's run this

okay cool so i have this fruit banana

showing up

now how would i randomly select

something from this array

okay so let's make a function we're

going to call it

okay random selection from array

this is the function in here we're going

to put our fruits and now since this is

inside of a function you can say kant's

fruits and you can create a new fruits

here okay

and the scope of this fruits is only

going to remain within the function and

outside of the function this variable

will be unknown okay

and let's move this down here

and let's just run this function for now

so i'm just going to say console.log

random select from gray or let's say

random fruit

okay and let's say that this takes in

items

let's say it takes in fruits and it

randomly returns them okay

let's uh take this array out i know i'm

making go back and forth yeah yeah yeah

whatever just just

it's okay all right i know i'm making go

back and forth but it's all good

um

it's not supposed to be inside of this

function let's put it outside of the

function okay because i'm making a

mistake so it's my fault i apologize

for this confusion

and what we want to do is

you want to pass it a fruit and it

should randomly return the fruit so an

example of this if you call random fruit

and you pass it in

you know let's just say

or whatever you can pass it numbers as

well so if you pass it in one and two

it may be randomly returns two okay and

if you run it again it might randomly

return one

so that's what this array here does

all right so it's going to get fruits

and it's going to randomly select now

how do we randomly select so one thing

you have to remember is we have

math.random and this will give us a

random number okay so let's try it

math.random

and i'll get a random number now if i

multiply it by 3

i'm always going to get a number that's

going to be less than 3.

now to make these numbers useful because

right now there are these decimal

numbers which are kind of useless

we're going to floor

all of this we're going to call a floor

on this

all right so now when we press up and

keep running it press up and enter up

and enter now notice i'm only going to

get numbers between 0 1 and 2.

okay

so i want to be able to get

0 1 2 and 3. so for this the range

should be because this is 0 1 2 3

i should be able to select

randomly

between these four numbers right here

okay so in this case i might have to do

math

multiplied by four so then i get a

number between zero one and two and

three okay so i'll always get that so

keep running it i'll never get four i'll

only get zero one and two and three

sorry

zero to three

okay so that's the trick that's how

we're gonna get that now

this is this over here is the max right

for multi where i'm multiplying it by

four

that is the

that's the length

that i want it to be

okay so let's go

create a variable called max

length is going to

it's gonna be four or yeah four

okay and now i'm gonna write this

function i'm just gonna replace it with

max length

so now when i change the max length to

let's say i wanted to give me between

three items i just change it to a three

i run it and now i get between zero one

and two

so this is going to be dynamically

changing so in order to account for that

we need to pull from fruit's length

okay so we're gonna say math.random

multiplied by fruits.length this will

give us a dynamic array

and then we want to

wrap this in math.floor

okay and we'll say

random number

and then what we're going to do is we're

just going to return

fruits

whatever that random number is so it's

going to be 0 1 2 3 and 4 or whatever

whichever one right

now

let's run our random fruit function and

pass it our fruits that we just created

right over here

let's run it and let's see if it does

what we want it to do

okay so i don't need to say let over

here let's just hit run cool so i got a

pear let's try it again i got a banana

let's try it again i got an orange let's

try it again orange let's try it again

orange let's try it again orange banana

pear

pear banana

right so just randomly picking and it

never breaks

okay

so you can see how

this is working right every single time

i run it

run

run

run i get back a different fruit

okay and so let's console log what

number is every single time random

number

okay let's run it

boom you can see the random number is

two

so it gets zero one and two so i get the

orange random number is one so i get the

apple one apple zero banana

okay so that's how this random fruit

function

uh

works so this is definitely one that you

needed to know because

in order to be able to do what you're

going to do in

rock paper scissors you're going to need

to know how this works

more specifically speaking there's going

to be a function in rock paper scissors

that you're going to need to implement

which is going to get a random computer

choice

and the array you're going to have is

going to be rock

paper

and scissors

and you're going to use need to

essentially lose the same logic to

randomly pull a computer choice out of

this array of three elements

rock paper or scissors

okay so you're gonna have to figure that

one out

one more thing you're gonna need to know

before we get into rock paper scissors

is

so this shows you select a random

element from an array that's what this

piece of code shows you

the next thing you're actually going to

need to know

is

some more advanced conditional

statements meaning how do you chain if

with an else if with an else

so you're going to need to know that

okay because that's how you're going to

be able to implement your rock paper

scissors game

so i'll give you an exercise

there are three different weathers

rainy

sunny and overcast

okay

and what we want to do is if the weather

is rainy i love rain so we should give

that a plus one score or a one score

uh we don't need to put plus one here

right

uh if it's sunny then we give that a

score of negative one because i don't

like sunny weather

okay

so i freaking love rain man like i love

rain rain is so awesome

sunny

um it's all right

and then overcast would be zero

i also i mean like for me i also love

overcast so

it is what it is you know um i would

want to give this a score of one but

since for this example we're just gonna

do this okay because i like rain more

than i like overcast so this is how

we're gonna do this app

weather scorer this is gonna be our

function

and how are we gonna do this so see if

you could give this a try and write

you're gonna need to write essentially

three if else if else conditions okay

and they're gonna need to follow this

pattern let's go ahead and do it

together if you can't figure out

yourself that's totally fine okay i'm

gonna give you five seconds five four

three two one all right let's do this

together now so i'm going to basically

say

if

so the the weather score right it's

going to take in an input from the user

so it's going to take in what the

weather is right now so we're going to

say if the weather

is rainy and you can use three equal

signs here as well or two equal signs

both will work in this case

if weather is rainy

and we'll also create a variable called

score that'll keep track of the overall

score

i'm going to say if weather is rainy

then we're going to do score equals one

okay

and now we're going to say elsif

weather

is sunny

we're going to say

score

is equal to

negative one

and now you could do an else because

we're just going to assume it's overcast

because those are three choices so you

could do else or you could also do an

else if okay because you can chain as

many elsifs as you want but you can only

have one else and then we're gonna say

else

score

is

zero

and then at the end we want to return

score

okay so hopefully you either got this or

try it now without like removing your

code from scratch and then writing it

again from scratch and you can try it

that way too and see if you can get it

and now we're gonna call

console.log our weather

scorer app that we just made

and we're gonna give our weather score

rainy and let's see what score it

returns

wait let's uh comment out our allure

fruit stuff up here

let's run it

and you can see we got back one because

it's rainy now let's try sunny

now that's a negative one

okay

and then we have

overcast

there we go

now if you want to take this to a next

level you could even chain these so for

example we could even chain these and go

uh if weather equals equals rainy and

maybe you can have two types of weathers

you can give you can have somebody can

give you multiple like um

weathers or something right like you

could get

they could give you it's rainy but then

there's also overcast

or you know it's a mixture of two so

then you can chain them together like

that so you could go

if weather is rainy let's just say i'm

giving i'm just gonna give a very rough

example so we're gonna say weather

and then we're gonna say whether two

and whether

[Music]

two is

overcast

then maybe this gets a score of two

because it's two of my favorite

weather's in one where there is rain

and there's overcast

all right so here's an example of doing

that yeah i have two other conditions

here and i'm checking if both are true

then score is one

now

let's go and pass both of these

conditions so i'll say

uh first weather is rainy and then the

next weather is

overcast right in this order oh wait

sorry

overcast let's put overcast here and

we'll say the score would be two points

in that case

so if whether one is rainy let's give

that a try and boom we got a score of

two

okay

so that way you can actually chain

conditions okay and then here let's see

if i can do this right so let's go else

if

and now we'll do another else if right

here

and then in this elsif i'm going to say

check if just the first weather is

rainy then give it a score of one let's

remove that

boom let's bring this all together so

now let's see if i pass just rainy

and maybe i don't even pass a second

argument let's watch what happens

boom i get a score of one

okay let's try

i pass sunny here and let's run this

i still get a score of one so watch

what's happening

this condition ran over here and it said

hey check if the weather is rainy and

weather two is overcast

okay

so we ran this and we saw actually you

know what this is true but this one over

here is false

because of this and statement here both

of this becomes false so the entire

things the entire thing becomes false so

then we don't run this check then we go

to this else if here

then we check

is weather equal to rainy it's the first

weather equal to rainy and we go yes it

is and then it gives it a score of one

okay and the order here matters because

if you put this statement above

well then

if the weather was rainy and overcast it

would still only get a score of one

because it would run this statement and

then just end

because it's chained with an else if not

an if

so else if meaning if this if runs then

this if will not run

but if you remove that with just an if

now both of these will run regardless

okay so that's why this statement elsif

is like an important one to keep in mind

and also you can check multiple things

why this will matter is in rock paper

scissors you'll have computer choice

here

and you'll have player choice here and

you'll need to compare if

you know rock

and maybe the computer picked or sorry

let's it's yeah so let's say computer

picked

rock

and you picked

um

let's say scissors or paper

you'll have to give yourself a score of

one whether you won or not

okay so if you want in this case you

have to give a score of one otherwise

zero otherwise negative one if you lost

so this will come in handy when you're

building that game okay so this is just

kind of foreshadowing that so this was a

little contrived example

but if you hung in there and you did it

great job pat on the back

and with that said i mean you're

you know at this point you're pretty

much ready to actually start building

out rock paper scissors i hope you're

excited all right i hope you're excited

we're now going to work on the rock

paper scissors app so let's go back here

now where you're going to find this app

is going to be in your projects over

here okay so let me go back to this here

so i i can get you a little familiar

with this if you haven't really been

familiarized with this yet so what this

is on this right hand side is you have

some lessons you have project exercises

and project solutions okay so these are

fully working apps

got it these over here are exercises

meaning when you go to rock paper

scissors in under solutions you're going

to notice that the entire app works but

if you hit refresh here and you go into

project exercises again and you go rock

paper scissors under project exercises

you will click and nothing will work

meaning that the entire app is made but

it's missing the javascript

functionality okay so

nothing dynamic is happening with this

app as a result of that so that's where

exercises will show up now to find where

to go and code these exercises on the

left hand side you have this folder

called projects so you're going to click

projects

inside here you're going to have rock

paper scissors i'm going to click rock

paper scissors so we're going to go to

rock paper scissors and here you're

going to see that this project has an

exercise and a solution and every

project will have its own exercise and

will have its own solution folder okay

so if you look at them exercise solution

folder uh the exercise folder has

your html your javascript and your style

sheet

solution has the same thing okay the

only difference between the solution and

the exercise folders is going to be the

script this is the only thing that's

different between the two okay these two

are not the same you will need to update

this inside of exercise

i would highly recommend do not look at

the solution sheet until you give this

project a try on your own okay that's

gonna be that's not good you're not

gonna improve like that okay so

seriously just like don't do it it's

gonna be a waste of your time waste of

your effort like otherwise why are you

watching this tutorial just don't watch

it go do something else right so if

you're gonna do it then do it right make

sure you do the exercise first and give

it your best attempt even if it takes

you hours or days it doesn't matter

do that because you're gonna get better

so let's go into you know this file

right over here uh let's so what we're

gonna do is we're gonna familiarize

ourselves with what's inside of here

okay um and then we're probably gonna

move over into a new rebel okay so i

want you to actually do this exercise

but outside of here because if you try

to do this here

it's not gonna be the best experience

plus i want you to become a better

developer so i want you to actually

create a new rupple with all three of

these files in there and then try to

code it up so you can see how to do this

from scratch okay so as a matter of fact

why don't we actually go ahead and set

up the new repel now and then we'll walk

through the code together okay so let's

go ahead and do that so hit open up your

open up a new tab

and then just go to replit.com just like

this

replit.com we're going to select the

html css javascript

okay click here

and then just choose uh great rapple but

we're gonna in this case say rock paper

scissors and hit create rubble perfect

now inside of here we just have index

script and style okay so we have these

three files now here's all we're going

to do we're going to go back we're going

to

copy so what i'm going to do is i'm

going to do command a or control a to

copy this entire everything that's

inside of this index.html i'm going to

copy it right click and copy

let's go back here

let's delete everything that's inside of

here

right click and i'm going to

[Music]

paste

boom just pasted that code okay so now

my html is pasted if i run it you're

gonna see it doesn't look very good but

it's there okay

then we're gonna go ahead and grab the

style sheet i'm gonna copy it

and we're gonna go back and we're going

to delete everything that's inside of

here i'm going to right click and paste

this

and i don't want you to worry about the

styling and everything i just want you

to worry about the javascript portion so

you can see that with the styling boom

everything looks perfect right

everything looks super clean now in our

script let's go ahead and copy our

script and don't worry this is not the

solution okay so just copy everything

that's inside of here so either control

a command a to select everything

and then you're going to hit copy then

come into this script and paste it okay

and hit run

and if you click nothing should be

working yet perfect okay this is

you starting from scratch and now let's

just walk through kind of what

everything is so let's start off with

index.html what's going on in here it's

a very simple file with only a few lines

of actual code all right some of the

code is

you know just doctype html html like

whatever right that's

default

html files come with that a couple of

lines of code here

and you're going to need to know the

player score certain div ids because

you're going to need to access them so

for example this button has a value

remember when we did red green and

yellow when we did that color app our

buttons had a value red it had a value

green it had a value whatever so then

when you clicked it you're able to

retrieve its value

that's why that exercise is going to be

val helpful to you here no pun intended

valuable for you

so

this is uh that's those buttons you're

going to need to know these classes so

familiarize yourself with this

index.html because from the javascript

side you're going to need to detect when

somebody clicks this button and you're

going to need to be able to refer to

these specific buttons you're going to

need to be able to refer

to you know just specific things and

then write on there

okay so for example when the player's

score shows up maybe that's the player's

score div when

the hands show up meaning the computer

hands or the user hands they should show

up here and by hand it's like computer

choice or player choice the result of

the game whether you won or lost that

should show up here as well okay um

obviously above that

red button right of course it should

show like above there so it should show

like here

end game button you're going to need

this id as well and this script here

just means that

this index.html

here

is linked with this uh

javascript sheet okay meaning if you

ever want if you ever change the name

here make sure you go and also change

the name here and make sure they both

match

okay cool but i would recommend you

don't change anything because once

you're done with your entire code you

should copy your working code and paste

it back inside of the script okay your

and the only file you need to change is

a script file okay awesome

now let's walk through this project step

by step we're not going to solve it

right now but i'm going to give it to

you as an exercise but we need to just

kind of go over some stuff okay

so

this project will have a couple of

functions that you need to implement all

right here we go

so if you look at this there's only one

two

three

four and five

there are only five functions that you

need to implement the code shouldn't be

like longer than 100 lines it should be

less than that probably around 70ish

lines without comments

and

that's what you need to work on okay

it's five functions one two three four

five six actually sorry six functions

you need to work on six functions now

with each function there's going to be

some documentation telling you what this

function should do how to run this

function and what it should return okay

and then there's going to be some other

notes sometimes if and you know within

the function as well so for example

let's walk through computer choice

well this function computer choice get

computer choice randomly selects between

rock paper scissors and returns that

string so that should be pretty

self-explanatory what that function

should do every time i call it here's an

example of me calling it get computer

choice and here's an example of it

returning a random string rock here's

another example of me calling it and it

returning a random string scissors

this function has no

arguments okay zero arguments nada so

you won't need to add in or take away

arguments the arguments are already

there

for you to help you out here's another

function you're going to need to

implement the get result function

okay this is going to compare player

choice and computer choice and it will

return the score accordingly meaning

here's an example where the human wins

aka you win against the computer when

you call get result and you pass it rock

and scissors so this is the player

choice and this is a computer choice so

when you give it rock and scissors

who wins is it the human or

the bot that wins this case the human

wins so then it should return a score of

one here's an example of a human losing

you call the get result function you

pass a scissors four player and you pass

it rock for the computer

and it returns negative one because rock

beats scissors and then here's another

example of human draws

where

you pick rock for the human and rock for

the computer and the score should be

zero okay so those are examples of how

to call this function what it should

return should return a number

and the two arguments that it has okay

this function is probably going to be

one of the most difficult ones for you

to implement and uh here i i have even

other notes for you to make it easier so

for example when you're implementing

this you're gonna need to have you're

gonna need to do a lot of if else if

else conditions okay because you're

gonna need to check if the

player picks rock and the computer picks

rock then what happens okay

so you're gonna need to write the code

here it says all situations where human

draws set score to zero so in order to

write this well this should be pretty

easy because

when's the only situation it's a draw so

you could say if a rock goes against a

rock that's a draw if a scissor goes

against a scissor that's a draw if a

that will take you forever or you could

just say hey if player choice and

computer joints match that's a draw so

you could do it like that all right

so that should take care of all of your

draw conditions then here are your other

conditions so

this is where all situations where human

wins you should set the score to one so

you're going to use a bunch of else if's

here and this is a situation where you

will define all situations where a human

wins so a human will win if

human pigs

you know

rock against scissors a human will win

if the human picks scissors against

paper a human will win if a human picks

paper against rock

so those are all the winning conditions

go here and then all the losing

conditions you can be pretty clever

about it and you don't even actually

have to define them because you could

just say else human loses okay so these

comments are there to help you kind of

simplify the logic for you a little bit

and then just return the score make sure

you don't forget to return the score i'm

going to toggle this function and close

it then you have the show result

function okay this function is also

going to be a little bit advanced and

this one

this function here get result is heavy

on if else conditions show result is

going to be heavy on dom manipulation

okay so show result is how you're going

to draw on screen and show stuff for

example if i go to the solution version

when i click here

show result is a function that's doing

you know human chose rock computer chose

paper

you lose

and then giving a score of negative one

and then drawing drawing it out here

okay so that's the show result function

so get result will calculate who won

show result will then output that the

human computer choice the human choice

the current score all of that stuff onto

the screen so show result updates the

dom to you win or you lose or it's a

draw based on the score also shows

player choice versus computer choice

okay

now

here

um

you can see it takes in three arguments

okay the score player choice computer

choice so it needs that in three pieces

of information and uh hint on a negative

on a score of negative one you should do

result.inner text you lose why because

oops if i go back here i have a div

called result right so make sure you get

this div by using element

document.getelementbyid get this div

right store in a variable called result

and then you could do result.intertext

and change its value to you lose so

that's what i said don't forget to grab

the div with the result id so this is

just a hint on how to like do one of

them you're going to need to do multiple

divs here then you have on click rock

paper scissors so this is where

what should happen when the user clicks

well right when the user clicks you need

to think about what happens so this

function should calculate who won and

show it on the screen so to give you a

hint this function should call upon our

get result function and our show result

function

that's kind of it okay that's what this

function will do

all right and then we have our play game

function this is going to be a really

important function

the name is a little misleading and i'll

kind of explain why

but here's what it should do

make the rps rps means rock paper

scissors so anywhere you see rps it

means rocket processors so make the rps

buttons actively listen for a click and

do something once a click is detected so

that's what the function of play game is

so all it does is just listening here

okay it attaches listeners to these

and once you click here it should run

this function right there when i click

here it should run that function right

there and of course we pass in the

player choice so

if i let's say choose rock

yeah

and um i click that then it calls on

click rps and then it passes in rock as

the player choice

it and then vice versa if i choose any

of these other ones and then on click

rps knows what to do so i have all the

notes here for you right so you make

sure to use query selectors select all

rps buttons

right and then i have even step by step

on how you can do it uh loop through the

buttons using a for each loop add a

click event listener to each button

and uh this is

you know um we can say add an on click

and this is something that we did

already with our color app okay remember

we had to add event listeners on click

to each update each button's on click

properties to basically listen for a

click and then call another function so

refer to that

red green yellow square app that we did

okay cool so that's what play game is

gonna be and then um you know and then

make sure that in there in play game you

also add a listener to this button too

so basically in play game all you're

really doing is you're just updating the

on click properties of each of these

okay that's kind of kind of what happens

there and last

end game end game is just gonna be a

function that clears all the text on the

dom so if i go here and i hit this

it just clears all the text so it takes

all the values that you had initially

set

sets them to empty string or empties

them out okay so i hope that you know i

really believe that you'll be able to do

this we've done

every single every exercise everything

that we've done up until this point

preps you for this project there

shouldn't be any

concepts that are new while putting them

together is gonna be harder and then

there's gonna be certain things that are

for sure going to be challenging so do

don't be upset or frustrated if you

don't get this honestly i don't expect

you to be able to get it you'd have to

be really really freaking hyper smart to

get this on your first try when i used

to do these projects i never got this

these types of projects on my own like

right away in the start i would give it

my best i would come close but it

wouldn't be working and then i would

actually look at the real code and then

i would go ah okay then i would try it

again but i would give it an honest try

so make sure that you do give it an

honest try and try your hardest before

you come and look at the solutions and

the concepts you know they'll be covered

are like for loops dom manipulation

variables conditionals template literals

event listeners higher order functions

and math.random stuff okay so

um

i think you're going to have a lot of

fun with this and really give it a try

and then pretty soon we're going to walk

through and build this together okay so

the next uh step will be us actually

walking through the entire solution

together but for now you should stop

take a break and try to build this

together by yourself

all right see you soon all right let's

go through and code up rock paper

scissors together let's go

so

let's go and do this step by step all

right and we're gonna walk through and

do every single thing together so this

get computer choice function over here

remember we made this function that

allowed us to get a random item from an

array right fruit item we're gonna use

very similar logic to that so uh let's

go and say

and i'm coding this live together with

you so if i get stuck in any of these

parts it's live

yes i've coded it up before but now

we're doing it from scratch so we're

gonna get so here are the rps choices

okay so we have rock we have paper

and we have scissors

these are the three choices that that

are universally available to us right

and now i'm going to just say

and let's capitalize this r

p

s

okay and now we're gonna say we're gonna

randomly select one so random

choice

okay and then here i'm going to do

math.random right and

we're gonna multiply that by three just

hard code three in there because we only

have three choices so this will make

sure that it gets the number between

zero one

zero and three

okay

and then we're gonna call mata floor on

this so remember because math.random is

always going to give you some

like

crazy numbers zero point eight four four

four four four something right but when

you floor it it'll just

remove all the decimal places and then

round it down so now this should give us

zero one and two perfect that's exactly

what we're looking for and then all we

wanna do

um is

let's let's actually call this random

number and then we're going to do uh rps

choice

pass in the random number and then

that's it we should just return that

okay so return

random number so if this function let's

see if this function is good to go and

if it's working okay so i'm gonna go

ahead and call this here we're going to

say console.log actually here's even a

cooler way of testing this

so let's just copy this function right

over here copy paste it in

hit enter

alright so basically what all we've done

is we took this function and pasted the

definition inside of our console and now

let's just call computer choice

let's call it again let's call it again

let's call it again and you can see that

every time it gives us a random choice

rock paper scissors everything is random

okay

so this function is working correctly

okay so i think that's great now let's

move on to the next function

this is going to be a little bit of a

harder function

right this is the get result and it's

going to compute the score so based on

the score that we give it it's going to

say whether you won or you lost so now

what are all the situations where a

human draws this one over here is simple

we're going to say if player choice is

you know equal to computer choice

well in that case we're just going to

return a score of actually

let's have a variable here here called

score

and we're going to basically just say

score equals

zero these are all of our draws

situation so now all of our drawing

situations are handled

now we have our else ifs

that we're gonna start okay so else if

actually let's do it this way

uh we're gonna say elsif

so now we're gonna have a bunch of

elsifs

so what are the situations where a human

will win so

let's pick a situation where a human

will win if a human chooses rock

then let's pick a situation where a

human will win where they pick paper and

then let's pick a situation where a

human will win if a human picks scissors

okay so those are the three different

situations so let's give it a try

so we're going to say

if player choice

is

rock

and

and uh make sure to always have

everything in title case like this

because if you use lower r somewhere for

rock and capital r somewhere else your

entire app is going to break okay so

just be consistent with uh this

spelling here everywhere all right let's

go here and let's give it a try so

computer

choice so rock will beat scissors

so this is situation one where a human

wins now let's try another let's see

another situation here

okay so i'm gonna copy this

and paste this here right

so these are now we're making all the

situations where a human wins

and we're going to set the score to one

in this case

now we're going to have another elsif so

i'm just going to copy this and paste

that

okay and uh let's also let's actually

copy i'm gonna copy

this entire thing and paste it again

copy this entire thing and paste it

again so in the situation of rock and

then we need to handle situation of

paper and then we need to handle

situation of scissors so paper

if a human chooses paper well what would

the computer need to choose in order for

the human to win

let's think that think about that right

so if i chose paper well paper beats

rock

so then we're going to pick rock here

and then scissors beats paper so we're

going to put paper here

so now we've defined all of the

conditions where a human wins so we're

done with that

and then the last thing we actually just

need to do

is define a situation where a human

loses so

what we need to do here

is just say else

score is uh negative one

okay so now everything else is a

situation where it's reversed where the

computer wins

but we can we can be really smart and

cheeky and just say else here okay

otherwise you would have to do a bunch

of elsifs and then you would have to

basically reverse this

and put all the choices where computer

wins and manually define each one of

them but if you do it this way you don't

have to define each one of them right

and then at the end all we need to do

thanks to this note this note is pretty

much giving away the exact line of code

you need to write

make sure to return the score

okay

return the score now let's take this

function and see if we can copy this and

let's see if we can paste this function

in the

command line we pasted it and let's call

our function get result

and i'm going to give it a player choice

of rock and then the computer will be

scissors and let's see what happens

and we get one is that true does rock

beat scissors yes it does so we get back

one what happens if both are rock

zero so that's perfect

let's try let's try all these test cases

right to rock scissors

we tried rock rock now let's try

scissors rock and we should lose

scissors

comma

rock put make sure to put those quotes

and let's run it

and indeed we do lose so all of these

test cases that we have written here

right check out what we have written out

here

so this function is gucci this function

is doing what it's supposed to be doing

so we're good on the get result function

okay so i think

we're good with that so we finished get

computer choice

we finished get result okay now let's go

through some of our

other functions that we're going to be

doing as well so let's let's go to our

next function show result

well before we do this

before we just like do show result kind

of in one go

let's just attach our listeners first

because that's going to be the most

important thing because if if i was

making this app the first thing i would

do is add listeners because if i don't

add listeners

i'm never going to be able to see really

anything happen

so let's go ahead and add listeners so

loop through the buttons using a for

each loop okay so let's do that but

first what i need to do use query

selector to select all rps buttons

so let's do it

rps buttons i'm going to set document

dot

query

selector all

and we're going to pass it

rps buttons let's go to our html file

and if you see here we have rps button

class right class rps button class rps

button so it's not plural it's singular

and let's just see if we can actually

console log this out so let's go ahead

and console log rps button

okay

and uh here we we are calling the play

game function so if i hit run everything

should run

and there we go we're seeing that we're

getting three html button elements which

is exactly what we expected

right

and now you can either manually attach a

listener to each one of them so you

could do rps buttons

you know zero

dot on click and we could say

um you know just

console log the

uh the value we could do that

rps button

zero right and then you can just do dot

value so this is like this would be a

way of hard coding it but that's not

what we want to do so when we click rock

it does detect that we're clicking rock

when i click paper it doesn't work when

i click scissors nothing works right so

let's go ahead and now do what the

instructions say here so it says use a

loop to

go through them so i'm going to say rps

buttons dot

for each so that will allow me to loop

and for each button

okay rps button

i'm going to do something so for each

rps button we're going to add an event

listener so let's go ahead and do that

now

for each button

on click

we're basically going to say hey every

time i click you

i want you to call the on click rps

function

okay

and then step four is make sure to pass

the currently selected rps button as an

argument

okay

so or the currently selected

so basically if i click this

then i need to pass this to on click rps

okay so let's go ahead and do that

so i'm going to basically pass it the

value of that so we're going to say rps

button dot value so loop through the

buttons

go through them and then for each button

give it this function

okay

and now if i hit so if i hit run here

and i click nothing is going to happen

right now but let's go to our on click

function and here i'm just going to say

console.log

and we're just going to say console.log

playerchoice

so let's hit run

let's hit

and now you can see every time i click

rock it prints it out

when i click paper it prints it out when

i click scissors it prints it out as

well so now the rps button f loop is

doing what i wanted to do

and i'm going to just remove all of

these notes because i don't need them

anymore

because we just essentially did all of

this that it was asking

okay

and um

yeah so play game button is done

on click is detecting the click so that

is good now what i can do with the on

click

is

we have the computer choice already

ready to go

right and we already have the get

results function so we can pretty much

play rock paper scissors at least in the

command line like we're we're pretty

much done with rock paper scissors here

so

i'm gonna basically say con let's get

computer choice

get comp choice

or

computer

choice and we're gonna call that

computer choice function so let's try it

get computer

choice

and let's just console.log our computer

choice

okay

so now we should have and uh what we'll

do is

put it as an object so then it'll tell

us like what's the computer choice and

what's the player choice let's run this

and click and you can see player choice

is rock and computer choice is scissors

i'll click again

this time player choices rock computer

choice is paper i'll click here

i click this one right now so it says

our choice was paper computer choice was

rock so our get computer choice function

is working correctly that's really good

okay

well

now since we have player choice and

computer choice guess what we don't even

need to see how this get result function

works

we just need to call it now baby and

have it return the score that's it

so

let's go and do con score and we're

going to just say get result

and we're going to pass it the player

choice

but make sure you pass it in the right

order and we're going to pass it the

computer choice

all right

and then we're just gonna console log

the score here

okay and uh

make sure to just put it as an object so

it just looks nice let's hit run boom

look at that player choices rock

computer choices paper and the score is

negative one meaning we lost right

because paper beats rock

let's run it again we chose paper

computer chose rock paper beats rock so

we won this time let's choose scissors

and we lost because we chose scissors

and the computer chose rock and we lost

let's try scissors again and we won

because we chose scissors the computer

chose paper and the score is positive

one

meaning that we won

okay fantastic so guys the whole

thing is working you guys this is really

really exciting now the only things that

are left are we need to keep track of

the overall score of the game so every

time the score updates we need to

actually keep track of that score and

increment it

now what we could do is we could

actually create a object to actually

keep track of both of those scores and

we could put that object all the way at

the top why are we putting it all the

way at the top

so every single function can have access

to it because it's like a database okay

so

it will have all our scores we'll say

const

scores okay and then this will have

a computer score

okay and it'll start off with zero and

then it'll have player score and that

will start off with zero let's give it a

more descriptive name and let's call it

total score

okay

so this will be the total and we will

update it depending on you know whether

the computer wins or the player wins

right or the human wins

and where will we do this well what we

can actually do is we can do this inside

of our get result function

okay

so we can actually update this object

right over here directly

so inside of our uh get result function

you could pass it

the total score

right and then we could actually do that

update that so i'm gonna give it i'm

gonna say total score

let's pass it in

i changed my mind let's not do it in

there because this function is very pure

let's not pollute it

with other

things and this happens very commonly

you know as a developer you go back and

forth a lot because it's normal to kind

of go back and forth and then decide you

know what i'm going to keep my leave my

code clean because then otherwise this

function is going to have too many

dependencies and it's going to be kind

of annoying so let's leave that as is

we're gonna update this total score

after we get it right so let's say that

uh i i on click i get the computer

choice i get the score

well then i update the score based off

of that

okay so

i'm gonna basically go and say

get the total score

and we're gonna grab the

uh we're gonna grab the player

score and we're going to increment it by

whatever score

whatever whatever we get as a score okay

so this way for now we'll just keep

track of the player score you don't

really need to keep track of the

computer score

i will leave that to you to implement as

a

challenge okay but for now

we'll just keep track of the player

score and increment the player score

okay

and then let's console log

total score

and now let's play this game

so rock

so player score is negative one let's

play rock again so now this time we won

right so last game we lost the player

score became negative one

this game we won all right now all

that's left to do

is updating the dom to actually show you

one or you lost or you drew

so let's go to our show result function

this is where we're going to be doing

dom manipulation right

is we have a couple of different

scenarios we have a scenario where

we could say we lost right so

if

score

is

negative one

then do something

else if

score is

zero

then do something right

else if

score

is 1

or we could just say else

do something right so in this case

if we

want then what we want to say is

you or sorry you lose

okay in this situation we would want to

say you drew

or

it's a tie or something right so let's

put double quotes and now we'll say it's

a tie

and here we can say

u

1.

now we need to do something with these

strings because right now we're not

telling the computer to do anything

right so we're going to create

uh we're going to get the divs so let's

get the resultive

and this is going to be we're going to

get this by doing

document dot get element by id

[Music]

and i believe the id is called result

let's go take a look and we have result

here

okay we have result

we have player hands and then we have

player score

okay hands and then player score

okay let's go back

hands div is going to be

document.getelementbyid

and we're going to do hands and i

believe

this div player score we're also going

to need that so let's go const

player score div

document i get element

id

player score okay just like that in the

in a case where we lose right what we

actually want to do is we want to say

result div dot inner

text

i want to set that to you lose

and then we're going to do the same

thing here and the same thing here

okay

so let's see

what happens

now let's give it a try so i'll run this

we win

and i'm not seeing anything yet so let's

go and debug what the problem is so

resultive let's make sure that this

result div is

the actual div that we want so i'm going

to console.log or

actually we i don't think we're calling

the function show result anywhere

so let's go ahead and work on that now

so remember

on click rps what it should do is

calculate who won and show it on screen

right so

line 74 calculates who won

right then we update the leader the

total score

and then we want to show on the screen

who won so let's go ahead and do that

now

i'll do it at the bottom here

and we'll call our show result function

and it has a couple of arguments and you

can see it's telling us it has the

argument of

score

what other arguments do we have let's go

check let's go check player choice and

computer choice

so we're going to give it the player

choice

and then we're going to give it the

computer choice

there we go player choice computer

choice

okay

that's um

[Music]

that's effectively it that's all what we

need to do here so let's give it a try

now run it

boom and it says you lose and it that's

is that true that we lost right we got a

score of negative one let's try again

you won

and now look it says

um the score is one so i win and then

the total overall game score right the

total score it says is zero player score

is zero now because we won

and now it's a tie so everything remains

zero zero zero let's run again i lost it

goes back down to negative one

all right now one a bunch of times

dang my score is just getting worse and

worse

okay all good so our score is

working the way that we want it to work

right

so what we want to do next

is at the end we also want to update the

scores

okay

so let's go ahead and do that so let's

update the score div now so or actually

let's do hands first because that's

really important

so we're going to say hands div

dot inner

text

right and it's whatever the choices are

that the player choice and computer

choice so i'm going to say

player choice

versus

computer choice

okay let's run this and let's see what

happens rock versus scissors

paper versus rock

scissors versus rock

okay so that's working but it's not

really easy to tell which one is the

human choice and which one is a bot

choice what i'm going to do is i'm just

going to put an emoji here and an emoji

there

so here i'm just going to make a person

emoji

and then for this i'm just going to make

a

robot emoji

let's run

this now when i click you can see that

it shows a robot emoji a human emoji and

a robot emoji

right

and then all we need to do is just make

sure that the score

shows up

like

here right score score should show up

there

so let's go ahead and do that now

and i'm gonna

[Music]

access the player

score

div and grab its inner text

right and then we're just gonna get the

total score

and we're gonna set that total score

to

yeah that's actually it i don't even

think we have to do anything the total

score should just be this and we should

be good so let's run this now this

so it's bringing the total score as an

object because it is an object so we

actually just want the player choice

score so player score

let's run it

oops undefined so why is that undefined

let's see player ah player score not

player choice

run

boom negative one boom negative two

right if you want to make this

fancier or whatever you could put this

inside of template literals and you

could say your score or something

something along those lines if you

wanted to right you could say your score

say one two zero one

whatever

and there you go

now let's open this up in a

full tab

right and let's take a look at this

let's play this game

click rock versus rocket to tie click

again rock versus scissors you won

rock versus rock it's a tie

i picked rock computer picked paper i

lost right and my score is being updated

automatically let's just play a ton of

games and let's see what happens

all right we're getting on a

oh we lost a lot of games there

right so there we go so the computer is

doing a good job and uh but but we beat

the computer right that's what matters

we want at the end

so let's go back

and now if i hit the red nothing happens

so we just have to make the red button

work

so first

let's do the following so we're going to

say

const

end game button

and we're going to say

document.getelementbyid

and i think it's end game button if i'm

not mistaken so let's go back

let's look

and i have a button i gave it id of

endgame button so let's go back here and

we're going to say endgame button just

like this

all right and we just need to

connect it so we gotta go

[Music]

endgame button

dot on click

and on click we just wanna run our end

game function that's it

okay and in our endgame function what

needs to happen is it should just clear

all the score so in our endgame function

we're gonna grab our total score

okay let's actually pass a total score

total score right here

that's just to signify that we're

passing it the total score okay so we're

signifying that we're passing this

that's why we're making a dependency

and we're getting the total score

because the global variable that the

whole our entire app has access to this

total score

okay

so this function is going to take total

score

and it's going to set the total score of

the player score

to zero

and then we're also going to set the

computer score to zero here

and we're also going to just erase

everything that we see on the dom

okay so let's go ahead and grab our

all of our divs i'm going to copy them

from here

i'm going to paste these divs here

and then we're gonna grab their inner

text and set it to

empty

right and then we're gonna do that for

both of the other divs so paste paste

double click copy double click paste

double click copy double click paste

and that should make everything empty so

i think this should be good for the

endgame function so let's go ahead and

try this run it

play play play play hit the red button

and everything clears up run run run run

hit end

and you can see that everything is

working

okay

perfect so there you go this is your

entire app right let's go and try it

the entire app is working hit the red

button it stops starts again

okay so the challenge for you is see if

you could add

player score

player score and then computer score

and see if you can see if both of those

get updated as you play the game

right that would probably be the best

version of this app if you can make that

work that'd be really nice

and with that said we're essentially

done with this so all you got to do now

is try copying all of the code here so

command a command c or ctrl a and ctrl c

go back to the exercises that you know

the

where you were working on this

javascript course rebel so go back to

that

and then go to this exercise

folder go to script.js right

and see what happens if you paste your

entire code over this

so if you paste your code over this

and you hit run

and you go to

rock paper scissors project exercises

your game should run

just like that i'm going to command z

and undo all of this

all right

there we go

so you should be able to paste it in

here and i recommend that you do so then

you have this

fully working

okay and then if you want to delete all

the comments you can from this to kind

of make it make it a lot cleaner

but

at this point right the whole thing is

you you've done pretty much the whole

thing i'm going to remove all these

console logs

from here just so you could see this in

an easy

easy to see way

like this on click function you'll

realize is the main function right it's

the entire

kind of game logic that happens

that happens here

and um

we get the computer choice

we already have the player choice

we compute the result based on player

choice and computer choice

we update the scoreboard

and then we show that score

on the screen

so this is like the main logic of the

game right this is where your main main

main logic is happening

so i hope that this totally made sense

you understood every single step by step

parts of this

and this was a lot of fun for me to show

you i hope it was fun for you to

actually learn this and you enjoyed it

but that said i love your beautiful face

and i'll see you

shortly

time to learn apis or how to get

pictures of random dogs every single

time i'll refresh refresh again refresh

again and different dog different times

do you want to make this well guess what

you're going to need to learn how apis

work and don't worry we're going to keep

it bare bones very simple easy to get

started so

that way you could learn and not be

confused on

what is going on

now in order to learn about this let's

go ahead and code this up together from

scratch so hit command t and let's go to

replic.com all right so this is a

platform where you can code super easily

right if you've been coding along thus

far just choose html css javascript and

the app will be up and running right

away okay let's go ahead and do that and

for the name we're just gonna say dog

api playground okay this is just for fun

and we're just gonna test this out okay

now

it's going to give me a random

index.html file a script file and style

and script is already connected with

index for example if i do console.log

and i say hello it's going to show that

hello right there all we're going to do

here is let's add in a random div i'm

just going to say div and we're going to

say id for id maybe i'm just going to

say

dog image or something like that and

then we're going to give it an inner

html of image like this okay you'll see

why this is important because we're

going to manipulate this from our script

file okay so let's go grab dog image now

let's just play with

the

apis first okay so the url that we're

gonna need for this

is this one right over here okay

https colon slash slash dog dot ceo

slash api slash breed slash image slash

random now

for you what i'm gonna do is i'm gonna

go ahead and add this to the playground

so you'll have access to this okay so

i'm gonna create uh api section over

here okay we're gonna say apis

so if you're watching this javascript

tutorial you'll be able to

get access to this url okay so this is

for the dog api right i'll just say dog

api cool so you can go ahead inside of

here and and copy this okay let's go to

our brand new repo that we had created

and in here we're just gonna

get access to this okay so what do i

want to do i want to

fetch this so we're simply just gonna

say fetch and we're gonna pop in that

url that we got so copy this url paste

it in here now there are certain new

concepts that i'm gonna teach you but

let's just go one step at a time okay

right now i kind of want you to just

follow along with me and we'll code this

up and then worry about what it actually

does in just a second so i'm going to

say dot then all right and this dot i'll

put it here dot then but this is the

same as if you wrote it all on the same

line by the way so eight being on line

five here or here is actually the same

thing but it's just that i don't want

this long to run in line to run

infinitely long so i'm just going to hit

enter here so it breaks it off into

separate lines now we're going to get

back a response and i'm going to say hey

return to a response.json i know this is

confusing right now but we'll walk

through it in a second and then

i'm going to say

hey get me that json okay and i'm just

going to have you

console.log.json all right so let's run

this and let's see what happens if

anything at all and would you look at

that what my code is doing is going to

this api meaning there you know what is

an api there's some data somewhere in

the cloud somebody else is hosting it

and we're going grabbing access to it

and bringing into our app this way we

can be lazy and we don't need our own

database and we don't need to figure out

how to get random dog images this

as long as you have access this link or

this api it will automatically get you a

different dog image every single time so

now i'm gonna and you know there's

examples of lots of different uh apps

that you know you could use your api so

you could use a movie api and then also

you can have you could build like a

movie app without needing you know

every single movie which has millions of

them right you don't need access to them

you can actually

get access to them through a database

that allows you to do that

all right so right now i am actually

getting a random dog image every single

time over here okay i work console

logging it out so let's go ahead and

copy it to prove it i'm gonna hit

command t command v and i'm gonna paste

it in the browser and you can see that i

actually got a real real image right

it's a cute puppy

i have an english bulldog as well so

you know it's kind of cute i like dogs

so here

i'm fetching this data and then once you

fetch it you have to do something to it

right away so this is where this dot

then thing comes in so whenever you see

this dot then thing this is talking

about promises

okay so promises is this like

weird confusing concept in javascript

because this

leads you into asynchronous programming

and all that basically means is up until

now you were writing you know uh regular

scripts you had this like list of

instructions that you would have the

computer do like you would say hey

you know run this for loop then go to

this array and grab this then do this

with that array then filter that johnny

depp net worth and show me that

different actors that was

like synchronous code meaning it runs

line by line when you're dealing with

getting data from somewhere else like

from a third party website all of a

sudden your code isn't synchronous

anymore meaning that your code doesn't

learn

run linearly anymore so here is an

example of this okay let me see if i

need to zoom in more that's good for now

so i'm going to go ahead i'm going to

say console.log say yo

and i'm going to paste that right

underneath this

and we're gonna run this

and you can see that this did not run

linearly right so

here let's prove this right so i'm gonna

delete that hello at the top

so run

first

and then this should run

third right because what should happen

is

and you would imagine that this console

log here would run seconds i'm just

going to say comma or actually let's do

it here and i'm just gonna say run

second all right so what should happen

is this console log should run first

this over here should run this console

long should run second and then this

console log should run third but when i

hit run watch what happens right run

first and run third ran first and then

run second showed up

so what is happening well we make a

request to this url so that's the same

as if i com pasted this right you saw

how this takes a second to actually show

you

a new dog image link right it takes a

few seconds one two one two

one two one two so it takes about one to

two seconds whereas this code right here

runs almost instantly okay so what

javascript decides to do is it says hey

i'm gonna run everything that i already

know so it already knows this it runs it

it already knows this it runs it but

this information over here right this

takes maybe two seconds so let's write

two seconds right here that takes two

seconds

once that takes two seconds and gets

resolved right this returns to us as a

javascript promise so

we just get back we're like okay we got

the data back

these dot dens what they do is we go

okay once we get that data back

then i want to turn that data into json

okay so we'll talk about what json

actually means so that's this is step

one right and then what we do with this

is we console log that json so this is

step two and i know this is really weird

notation but just.dense but you'll get

used to it after some point when you

start learning more and more about like

apis and asynchronous programming or for

now just like kind of memorize it that

whenever you have to do fetch you do

these two dot dens every single time and

you pretty much can copy paste this

exact type of code um every single time

you do a api request okay that's what's

happening okay and these are functions

so i'm just basically saying hey dot

then you know grab the response and turn

it into a json and what json does is

json turns the data essentially to this

object type of format that you see here

right so you have message and then you

have the url

and then there's another key so we have

one key with the message which is the

actual image for the dog and then we

have another key which is status which

tells you whether it was successful or

not and then that object ends right so

that json is really just an object with

two keys inside of it message and status

that's what this is

you know getting back and then once we

get that back we go ahead and console

log it out

this dot then

runs whenever this promise here resolves

okay now watch what happens if i let's

say

cut this right i'd remove those lines

and i just say console.log and we run

this

let's run this and you notice it just

says promise what the heck is that right

i can't really do anything with the

promise promise is a really weird thing

but when i bring that back

now something happens

so whenever you're dealing with promises

if you just call this it's going to give

you a promise but you have to do a dot

then

and this other dot then these two dot

dents chained together to pull that data

out

after your code runs and waits for two

seconds so this is an example of like

asynchronous programming and it's a

complicated way of just saying like

stuff you have to wait for

this over here is stuff you don't have

to wait for

right this is literally that's literally

all that means okay stuff you gotta wait

stuff you don't have to wait for stuff

you have to wait for and when you have

stuff you have to wait for

you have to do these dot dents

that's when you use them okay and then

they just call them these like fancy

names that confuse you like promises

asynchronous programming in your head

honestly between you and i don't use

those words okay in your in your head

just like

use simpler words so you can understand

it but like learn these words because

they're going to be helpful for you when

you're googling things right how do

promises work how how do you do

asynchronous programming with javascript

but like for yourself just go

is this stuff do i need to wait for

is this like a url or a database thing

that i'm doing yes i probably need to

wait a few seconds to get that data yes

okay then i just know that i'm going to

need to do dense google how to call how

to do a fetch api request google

how do i deal with promises google how

to get a json file from a promise

right so that's where your google skills

come in and stack overflow you go

there and you get the information that

you actually need

all right so hopefully

this part over here makes sense to you

and we're retrieving the data now we

want to take this

further okay so what we want to do now

is

we want to do this

right and then we want to actually

update our

we want to update our um

this right over here okay we want to we

want to update this right over here and

we want to like put the dog image here

so the new dog image that we're getting

all right so let's do this once we get

that json back right here then what we

can do is

once we get it back then we go ahead and

update

this dom right over here right and put

the dog image

so let's go ahead and do that now so i'm

gonna i'm gonna remove this console log

here and we're going to go right there

i'm just going to say console.log

json

right and let's run this

and this is the json that i'm getting

and i can see that this json is just an

object so if i actually did

json.message i should get

the contents of that message so i should

get this url right over here

all right so let's go ahead and try that

so i'm going to say json message and you

can see that i'm getting that that like

specific url that we need yeah all right

now that i know i'm pulling this data

all i have to do is just update

this dog image div and change its inner

html to a different image okay so let's

go ahead and get access to this i'm

going to go back

boom

and i'm just going to say

you know const

get or dog image

and it's going to say

document.getelementbyid and i'm going to

pass in this id

right and then all we're going to do

here is dot inner html

and let's do template literals here and

i'm going to say image

set set the source for the image

and the source for the image is going to

be

json.message

all right and then we'll just end this

image tag right there

so this should do the trick let's try it

i have a broken image so interesting

what's happening here i need to put

quotes around this let's give that a try

okay

boom there you go so now you can see our

dog images oh that's a cute dog look at

that

and i i have a i love pomeranians i just

think they're so cute oh that is cute

look at these guys

just playing

run right every single time you run it

you should now just be getting a new dog

image right so

this is working

now their sizes are kind of different

and a little bit all over the place so

in order to make sure that we have a

size that we actually like what we can

just say is i can pass the

uh height

and width properties okay so we can say

height is 100 and width is 100 let's try

running it now

and you'll see that we'll always get an

image of this exact size every single

time

but maybe we can make it 300

and 300

that way it'll be big but it won't like

completely blow out a proportion right

so there we go so 300 by 300 is not a

bad one

as you could do that okay so this is

just like a really bare-bones starting

example of apis and like that quickly

you have a up and running app

you know this is nice like if you had to

do this by yourself you know how much

work that would take you would have to

collect infinite dog photos manually

you'll have to download all of them then

you'll need like a file with like

hundreds of dog photos and then your

code would need to like go through that

file manually and like randomly select

the dog and then show that dog and you

have to keep that dog thing updated and

it's like

so much work but here somebody's doing

that for you with the random dog images

that they have collected and all you get

to do is just hit the run button every

single time and get a different freaking

dog

that's nice now what we could do is

instead of making this app where every

single time you have to like refresh

this app and get a new dog image that's

kind of like lame let's make it so we

have a button that says like get new dog

or get dog or something like that and

then every single time we click that we

get a new dog okay so you you have

enough information to be able to kind of

do this yourself

so if you want to challenge yourself you

could try it but if you don't and you

just kind of want to follow along that's

all right too

because we will have some exercises

coming up for you okay so don't have to

kill yourself here all right so first

thing i'm going to do is i'm going to

turn this into a function okay in my

mind i'm thinking about it like this i

want to turn this piece of code into a

function and what i want to happen is i

want this piece of code to run every

only when i click the button and

every time i click the button this piece

of code should run all right so let's go

ahead and add a button right underneath

this okay so this button can be added by

going into html hitting index.html right

here and right underneath here we can

say button

get new dog

let's

yeah let's give it an id of dog bun

okay let's run and now we should have a

get new dog button okay cool

now

what we want to do is i just want to say

hey every time i click that button so

let's go let's go grab that dog button

because i'm going to say const

dog button

go to document

get elements by id

there's a dog button okay and here i'm

going to say dog button dot

on click

and we're going to set its on click to

just say you

clicked get new dog okay so it's just

gonna say like hey i noticed that you

click get new dog okay so click it click

it click it click it every single time i

click it

you'll notice that at the bottom right

here

it says get new dog right so

it is working click click click click

click

okay perfect so it's doing

what it's supposed to do it's detecting

the click now what i want to do is i

want to run

this fetch request on click so let's

wrap this bad boy inside of a function

so i'm going to say const get

new dog okay and we're going to turn

this into a function and we'll do it

like this and i'll take this code and

i'll paste it in here let's format it so

it looks beautiful

nice

so now what this is doing it get there's

a function called get new dog when we

call it it fetches this data it fetches

this url

uh gets a response

like console logs the response right and

then it like updates the image now we

don't even need this console log here so

i'll just remove it

so all this does is

gets the url and then updates the image

with the new dog

thing

all right and

here what we're gonna do

is we're just going to go ahead and call

that function so i'm just going to say

get new dog

like this and we're going to call this

function

okay let's run it

run our app and now what we're going to

do is we're going to say get new dog and

boom it just got us a new dog let's hit

it again get new dog boom got us a new

dog get new dog getting you right that

is so nice and now that dog button every

time i click it that button is doing the

work for us and we don't have to like

kind of do anything right that's nice

uh if we want we could put that button

at the top as well so what we could do

is let's go to index.html i'll take this

button from here i'll kind of move it at

the top right there and then this hello

world i'll just completely remove it so

if we go to our app we have get new dog

right at the top

you click it you get a new dog you click

it again you get a new dog again

if you want you could give everything

kind of a margin

but we don't really need to do that for

this we can just keep this up oh that is

cute um i have english bulldog that very

similar

to this

yeah she's adorable she has huge paws

man

so yeah so this get new dog thing is

working

kind of honestly how we wanted to and

it's really

kind of straightforward so

not too complicated honestly like

it works it makes sense and what i'll do

for you is i'll take this lesson right

and turn it into a lesson in our main

like javascript app that we were working

on and i'll put it in here for you so

then like you can actually go through

this

api's lessons right so okay i'll make a

new folder that way it's like clear it's

like dog related right and then in here

i'm just gonna add

an index.html file

i'll also add a

script.js file

and then you don't really need a style

sheet for this because there's not much

style so we'll paste the javascript code

that we wrote

we'll go back to this app and i will

grab the index.html i'll copy this

and we'll go ahead and paste that

index.html

code in here for dog random

so what's nice about this now is

right over here on the right hand side

right you'll have under lessons you'll

have api lesson for get random dog

you'll be able to click it other people

will be able to see that you made this

too and you just hit get new dog and

you'll get a new dog every single time

and then in order to

like actually see the code for this app

you can go ahead on the left hand side

go into api

go into dog random

and boom you'll see it right here

so this code is like the solution is

there for you if you need it this is

going to be the

uh little project that we just made okay

and then we're going to like do more

practice stuff with apis okay so we're

gonna get to it right now but hopefully

like

this app makes sense for you so far

all right now we're gonna build another

app with apis and this is going to be a

superhero one and you should try

to kind of make a little bit of it

yourself as we go along but they're

going to be certain concepts in here

that might be new for example like

access tokens but this superhero api app

is going to do the following every time

you click get new hero is going to

randomly select the hero show you that

heroes intelligence or durability or

attack power or speed or something along

those lines like stats you know so for

example if you typed in get random hero

it might bring a batman or if you typed

in another hero it might bring up let's

say spider-man and so you should be able

to do that with this app now if we want

to really take this app to the next

level

you can try making it where you can type

in the name of the hero like batman and

hit enter and it should automatically

pop up batman's image and it should show

batman's stats or maybe his biography

and then every single time you type in a

new person and say get hero it

automatically does that every single

time okay so this is what we're gonna

code up let's go ahead and do this

together step number one go to

superheroapi.com

it should bring you to this page where

it says get all superheroes and villains

data from all universes under a single

api

all right

so now here's what you need for this

you're going to need it's going to

generate an access token for you so

you're going to need to connect it with

your facebook if you don't have a

facebook go ahead and create one it's

free make a dummy one come here connect

it okay so do that

and then you'll have a

account access token okay so once you

log in with facebook this token is gonna

be important because without this token

this api will not work so make sure you

have that and then what you're going to

need is this url right here okay this is

going to be your base

url then for this api there are a couple

of other things that that are helpful to

know for you is

how this api will work is you'll need to

either pass in the id of the hero or

you're going to need to search that hero

okay so if i for example go here you can

find the character ids here

you'll be able to go here and see all

the heroes right so you have ethan hunt

you have evil deadpool

you have spiderman

right over here right you have batman

hawkeye you have thanos so you have all

these heroes as either you pass in their

id so for example you saw that the id

was two four five so what that basically

means is what your url will look like is

the following so you'll have https call

superhero api.com

slash api slash whatever your token is

so i'm going to go ahead and copy my

token and then we're going to go ahead

and paste this

oh sorry let's go ahead and do this

so

right so

api.com api slash

whatever just imagine that that says

your access token right here okay your

access token

slash you're gonna type in id

slash whatever hero that you want so

let's say 245 or whatever it is okay now

if i try to go to this url let's see

what happens and let's make sure i bring

my

access token and repl i'm going to

replace this part with my access token

let's hit enter and let's see if we get

anything if it works at all right you

actually just say

245 here just like that okay so let's

try that

and you can see that i'm actually

getting the data back on ethan hunt

and i have power stats on him so his

intelligence is

strength is pretty low 11

speed is kind of low

uh durability is low but then like

combat is pretty high

right ethan hunt

and then he has a place of birth which

is wisconsin i did not know that okay

his height is five six

uh what's his occupation he's an agent

he's a training officer

and um yeah and then here's his image so

i can actually click that image

and boom it shows me

okay apparently

it's uh tom cruise okay that's what i

expected

so let's go back here

so this is the basic this is a call like

a sample call reference okay so this is

going to be useful for you

and now we can actually just start

coding this up so let's go ahead open a

new repl so let's go to replic.com

replay.com

okay and then just go ahead and choose

that html css javascript one that's the

one we want and we're gonna say

superhero api okay let's go

cool

and in here we're gonna do kind of a

similar thing but this time we're going

to say get super hero we're just going

to create a function right from the

start

all right and then we'll just say hello

[Music]

and we'll just call this function let's

just to make sure that this function is

working

and make sure to put an equal sign here

and run this

okay now you should it should say hello

at the bottom right there and you don't

actually even need to do console log

here just run this because it already

has a console log

and you can see that we're getting back

hello

perfect so seems like our get superhero

function we created it we are able to

call it now

inside of this function what i actually

want to do

is i want to make that fetch request so

remember that

fetch requests we made earlier you can

pretty much go ahead

for a dog random

and look at it and your fetch request is

going to be very similar to that

all right so remember it's fetch you

pass in the url and then you do these

dot thens

so let's go ahead and

do that now okay so i'm going to

basically say fetch

and let's put that

reference url there so we have we can

see it at all times

and now i'm going to

basically

uh use the url right so

let's go ahead and do that i'm going to

paste

and character id here is going to be

let's just say 245 because that's ethan

hunt and for access token i'm going to

go back

and copy the access token so copy

and

let's paste it in

in place of that where it says access

token

okay replace that with just whatever

your token is and uh this is what you

should have now one really really key

hack that i'm going to show you here is

make sure to put php here if you don't

put that this will not work i know it's

pretty weird but this is a weird hack

that i had to kind of find around it

and it's just for the superhero api okay

you don't ever like need to do api.php

like that okay

so there we go this should get the ethan

hunt guy and then we just need to do the

two dot dens that we've talked about so

i'm going to say response

get the response as a json

and then we need to do something with

that response we're going to say then

once you get that

we're going to say json and we're going

to say

console

log that json

okay so

with fetch requests you can pretty much

like

copy paste these lines almost every

single time

and then fetch of course is just going

to fetch that's not going to change the

only thing that's really going to change

is what goes in here

okay

so i'm going to hit run on this and

let's see if anything works and boom

look at that we are getting ethan hunt

we're getting that data

right over here

uh just as we want it to

okay so we get response success id is

245

name is ethan hunts and then we're

getting all the power stats that's

perfect right now if i wanted to get any

one of these specific things i could do

like let's say the dot id or dot name

let's say i just did dot name and let's

run this

i should just get back i should just get

back ethan hunt okay

if i

ran and i looked at this and i wanted

power stats right i could do

json.powerstats

and that should get me back

just the power stats

and then i believe image should get you

the image

yup

right and then you will have to do dot

url to get the actual url out of that

because it's an object within an object

okay and now we have access to the url

and if you use an image tag you can

actually then pop that up on the screen

there

so what we'll do in order to attach that

image

to like basically your app

is i'm gonna go ahead and i'm just going

to say hey get the document

dot like query selector all right and

we're going to query select and grab the

body tag so that's

this tag right here

all right i'm going to grab the body tag

and then to the body tag let's uh let's

add something so i'm just going to say

plus equals okay and we're just going to

write like

i don't know hi

or goodbye something like that let's run

this oh we want to make sure we do dot

inner html here so let's do dot inner

html

let's run this

and you can see that all we did here is

we just appended goodbye right there

okay

if you don't do plus equals and you just

do this it will replace everything

that's inside of the body and replace it

with goodbye and that's not what we want

right we just want to like attach that

so watch this right so this ethan hunt

that we're getting we have the image

here so just go ahead and copy that okay

uh right click copy that

and if i go const

image i'll just paste that there it's

that long url

okay

so now what i can do is i can just like

attach that image to the html body okay

so what i can say is i can just go and

go

i have

image tag right and then this image tag

will have a source

and this source

is uh gonna be

the image that we have

okay let's uh let's make this a template

literal so we can then write javascript

in there

all right boom

boom boom there we go

so we have this so image and then just

like in this like that

cool so image we gave it a source

and this is going to be the ethan hunt

image and it's kind of hard coded here

all right let's put this maybe in

strings is that what that wants yeah

that's kind of weird huh like it wants

that in strings even though it already

is in spring so kind of weird but

whatever

we can we're going to go ahead and do

that

and now you can see that this image is

popping out and it's actually not ethan

hunt i apologize it's amazo right but if

i change this

uh hero here you know then i could get a

different image but yeah so if i run

this i'm just going to get that amazon

image every single time okay so this is

apparently what amazo looks like i mean

i didn't even know that right

and we're going to give this a height

and width too so let's go ahead and do

height is

200 and then we're going to say width is

200 now in order to make this dynamic i

want you to try it because right now

every time i run this and even if i pass

in a different hero let's say i put in

245 and i'm actually putting in ethan

hunt

notice that it's still going to give me

a mazzo so see if you could

change something here in this function

where it could update this image

dynamically okay so give that a try i'll

give you five seconds to pause the video

and try it on your own five

four three two one

all right let's go ahead and now give

this a try together

so

i am getting back this data but i'm just

console logging it so instead of console

logging it what i want to do

is uh i want to grab the body and i want

to add this all of this to the body okay

so this is what i want to do so i'm

going to cut this because i don't need

that there i'm going to remove this

console

well you can keep that console log for

now i'll keep that console log

and

i'm just gonna say hey uh get me the

json and then just add that image now

instead of using this hard-coded image

what we're basically gonna do

is uh we're gonna grab

this image right over here so remember

we're gonna need to do

json.image

and then that'll give us this object

right here and then we're gonna need to

do dot url to get access to then this

url right here that key okay so let's go

here and we're gonna say json.image.url

just like this

so now i can remove that hard-coded

image that i had let's run this and

let's see if that works and boom i got

i got ethan hunt let's run it again

let's run it again let's go here

to our html and i don't want to say

hello world here anymore i want to

actually say button that just says get

new hero and we'll make that work later

and for bonus points you should try to

make that work yourself okay before we

even do anything else perfect and i'll

just add a new break line okay this just

like breaks

things on to a new line and then that

way the get new hero button always stays

at the top so let's get back to our

script

and um watch what happens if i pass in

20 and run it now it's going to get me

amaros

image if i run 40 and run it it's going

to get me

this guy whoever that is

uh let's hit 60

and it's running me that looks like bane

is that is that bane

he looks epic

yeah that's bane that's sick

and his relative is apparently king

snake who's his father yo i didn't know

that

that's lit that is super cool

man ben is a badass

now

see if you can make this get new hero

button works every single time i click

it i want to be able to get a new hero

every single time so i want you to pause

this video give this a try on your own

five four three

two

one

all right let's go ahead and try to do

this together it's all right if you

didn't get this i'm proud of you for

trying and i hope you tried

um because you'd only be cheating

yourself if you didn't

all right so

uh let's

let's do basically what we did for that

dog app right so we have our button

and what we want to do is

let's go give that button an id well we

only have one button so i can be kind of

lazy here and i can just select this

button

i can query select this button but is

that a good way of doing it not really

right like that's

no i don't want to give you guys bad

habits let's just say id

new hero

button let's just say that

let's go into our script

and we're going to get access button

kind of up top here const

hero button

new hero button

and i'm going to say document dot

elements by id paste in that new hero

button and so whenever that button runs

i want to run this function here so i'm

going to say console.log

new hero button

and i'm going to say on click run me

this thing gets superhero

and that's it so now when i run this app

everything should be empty when i hit

get new hero it should run but every

single time i run it it's going to keep

making a new request but it's going to

get me the same hero every single time

so getting your hero get new hero get

new hero get new hero it's getting the

same exact hero but every single time

and that's not what we want we want a

different hero every single time and so

now i'm going to give you another piece

of this exercise okay

try this on your own so see if you can

make it

where

it

randomly picks a hero okay remember that

array exercise that we did where we

picked random remember the when we were

making that color app right uh remember

or sorry fruits app and we picked a

random fruit remember when we did rock

paper scissors and the computer chooses

rock paper scissors randomly all right

so

you're gonna need to use some of that

knowledge to pull this off this one's

gonna be a little tricky but i think if

you really tried you could make this

number where it's random now if you need

a hint if you don't need a hint you

could pause this video try it on your

right now if you need a hint what i'll

tell you is this number is not going to

be between three like it is for rock

papers and scissors this number is going

to be between one

and

all the way till 731 because that's how

many heroes they have so you're going to

need to put a number between 1 and 731

uh in here so it should either go 1 or

731 or some number in between but never

lower than one and never higher than 731

okay so you need to make a function that

can do that

all right so take five seconds right now

i'll give you five four three two

one all right so we're gonna do this now

const

uh

random

uh i'm gonna create a function called

random hero

and basically what this function is

going to do

is

we know that there are 731 heroes okay

so khan's number of heroes is

731 and what i'll basically want to do

is i want to do math.random okay so

let's also open this up in the shell or

sorry in our console and give this a try

all right so let's go here and actually

i'll clear this up so you can see this

nice and at the top

so

let's say

i do math.random

and we multiply this by 731. now notice

that i always get a number between 0 and

731 but it'll never actually go up to

731 right so that's maybe not not what

we want we want it to actually go up to

731 so there are a few hacks you could

do here

so if we want to do so first of all

let's do math.floor

so math.floor will and if i hit up and

enter up and enter it's going to keep

going but it'll never actually pick 731

and it it's not going to be easy for me

to prove that to you here but it's not

and it's also able to pick zero and

that's not what we want in order and to

prove this to you guys what i can do is

like copy this piece of code

and just change it to a smaller like

number so you can kind of see this

so see how it goes zero and one but

it'll never pick two so it's basically

picking the lower bounds we want to

actually pick the upper bounds one start

with one

and end at 7 31. so

the way that you could do this is you

could actually just add a plus one to

all of these so this way when i run it

every single time i'm gonna get a one or

a two every single time so you could

just add a one or instead of math.floor

you could actually call math.seal so

either of those ways work so we're gonna

do the same thing with our function with

731 and just add a one at the end and

this is always gonna ensure that you're

getting a number that's greater than

zero and it doesn't end at seven thirty

it would unit actually seven thirty one

okay so this will get us

that so i'm gonna

paste this here okay now the 731 is

actually just you know number of heroes

number of heroes and then we're gonna

plus one this cool

and we're gonna say

and actually we can just return this

that's it

okay and then we can just call the

random hero function

here so i can just say a random hero

like that so get superhero and we're

gonna get a random

random hero okay you could because this

function here is just going to return a

number so for example if i

do this and we do random hero and

press up and enter it says run random

here is not defined interesting

but i just defined it

so let's try random hero now boom there

we go so every time i run random hero

you can see what it does right it gets

me

a different number every single time and

does a pretty good job right of

generating a random hero so that's why

we're just

running this random hero in here they'll

generate a random hero and then we'll

get that specific superhero and then

we'll get that dude's image so let's hit

run at the top let's go ahead and click

get new hero get new hero and

all right so we've had a little bit of

hacky

html here that might be causing some

problems so let's go to our html file

real quick and let's just

uh update this

real quick okay so what i'm gonna say

is um i'm gonna put a div here

and we're just gonna say id is hero

image

and then inside of here we'll just have

like an empty image thing okay and then

we'll just

update that instead so here we're gonna

say

const

hero image div

all right and then i'm going to say

document dot get element by id

and i think it's called hero image right

let's just double check

hero image

copy come back

paste it

perfect

and then we're just going to do

uh we're going to replace this part

right here

with hero image div and we're going to

change that html to this image so now

let's give this a try and let's see if

this is still working hit run at the top

hit get new hero

and let's try it and it works okay so

i'm getting new heroes

and look at what's happening their

images are actually showing up at the

bottom hit get new hero again

and so every time i hit get new hero it

actually like gives me a new hero so

that's great and why is this happening

so let's go ahead and open this app up

and let's try to figure out why is this

happening why is this behaving instead

of replacing the hero it keeps adding

them so get new hero

get new hero

i mean this is kind of a cool

functionality too actually i kind of

like this

uh i kind of like this uh version of the

app right every time you hit get new

hero you keep getting back

somebody somebody new so it's actually

super super super cool i actually

i really like this functionality but

let's say you want to change this

let's say you only want one hero well

what you could do instead of this plus

equals here which appends you could just

say equal and that's only just going to

replace so run this again hit get new

hero he'd get new hero and you're going

to get a new hero

[Music]

every single time

okay or you know not every single time

there is a one out of 731 chance that

you're going to get the same person

again probably lower than that

but yeah it's a pretty low chance this

is going to repeat itself all right now

what we want to do is we want to have

a search field here

and

you should type in there and then

um you should have a get new hero button

right next to it so you should be able

to type in what hero you're looking for

and then say get hero and it should

surge that hero okay so we should have

like kind of two buttons so one button

gets a random hero okay and i guess

let's just give this a name of random

hero so

uh let's go to our button and here i'm

just gonna say like

random and so when you click it it's

very clear that this is gonna get a

random hero okay and then what we're

gonna do is we're gonna have an input

which you you know is gonna be your

search button all right so let's go

ahead and create that input now i'm

gonna say input

and let's run our app and we should have

an input right here okay and then we're

gonna have a

button kind of like in front another

button in front of that input and this

is going to be search

okay let's run this so now our app is

going to have two things so random hero

will get you a random here every single

time

or you could type in a name of some hero

like batman and hit search

great so let's go back

to our app let's go to script.js

and let's work on this search

get you know basically let's get a hero

that was actually just searched

so i'm going to create a new function

well do i need to create a new function

let me actually think about it because

getsuperhero a bunch of the

functionality is going to be same just

this

uh this is going to change right so for

example if you search a hero

then it'll go

base url instead of id we're going to

actually do search.name of the hero

and if you pass in an id

okay so if they pass in a

name

then this is going to be the url

like

schematic or whatever right this is what

the url is going to look like and to

pass in an id

the url is going to look like base url

slash id okay and let's uh try that url

so let's go

grab that url real quick so i'll go here

grab this whole thing copy it hit paste

grab your token go back to that

paste this

token right here

and now we're gonna do slash search

slash batman and let's see if this works

as i expected or if it's gonna break

and it actually does work wow look at

that let's try spider

and yeah spider shows up let's try

spiderman let's see if that shows up

that's the wrong name so let's try

spider dash man

and spider dash man indeed shows up now

one thing if you have noticed is you're

gonna get back of basically the same

response regardless of

so you know whether you searched the you

you searched it up like

with the search spider-man

or whether you typed in the id of

spider-man which is i can see here it

says 620 so let's go ahead and replace

this here with

uh 620.

both of them are actually going to

return to you

pretty much the same exact

response right like the response is very

very close

the only thing i see change here though

is we have a results array like we have

a results uh key here

right and then the value of that is an

array

so basically it seems like it gets you

multiple results for spider-man

um one or multiple results and so

basically it seems like we would want to

pull

basically i think we would be safe just

pulling the first result that's the

difference between this and if i

actually just type in 620 because that

is getting me that specific spider-man

that i was looking for

whereas for this

it's getting me a array of results and

then the first result has the specific

spider-man that you might be looking for

okay so we're just gonna get like the

first

item out of that array that's how we're

gonna do it so let's go back so some of

our code is going to change not all of

it but just a little amount of our code

meaning

in one of the scenarios

so normally we just do json and we're

good but in this case we might have to

do

dot json.rt

get me the zeroth result

right

and

then

then i could do dot image dot url

unlike how it is currently where you

could just do json.image.url

okay so let's maybe let's put these

examples kind of this so you can see

right so

with this method i can just go like this

because i already know exactly which

json that i'm getting here i'm getting

multiple results so i want to pull the

first result get that results image url

so

a slight change is going to happen

whether is going to happen

whether we're given um a id or a name

so in that case for simplicity's sake i

think what i'm going to decide to do for

now is just create a different function

that way we won't have to do all this if

else conditioned stuff we can just have

a different function okay so this

function here let's rename it and this

should be get random superhero

that function we run and it essentially

will get a random superhero

and um

yeah and if it's gonna get a random

superhero i mean

you you really don't even need to give

it an id so

yeah so yeah you could call it get

random super get superhero i'll just

leave it as

uh let's go ahead command z this

let's just leave it as get superhero for

now just because i don't want you to

like have to change it everywhere like

for now you should just have a working

version so let's leave that as is so

this is one function now let's make

another function and this is going to be

called

get searched get search superhero okay

so this is whatever the user searched up

and this is gonna it's gonna probably

you know whatever the name the user is

searching for right

now we're gonna be able to copy a bunch

of stuff from here

okay so let's go back

for fetch request here

we're gonna have a

base url of course

but on the top of the base rail we're

going to say search

and we're going to pass in the name

so this is going to get us the

you know like put in batman or whatever

here

and then we're going to do our

dens.dense like how we did earlier

and

let's just

go right here and paste them format this

cool

you do our dense.dense and for json here

we're actually gonna grab the

we're gonna say const super uh hero

is equal to json.results

of zero

this is gonna be the specific hero and

then

we can replace that with hero.image.url

and uh instead of console.logging json

we're going to console.log our hero

and this search superhero function is

going to run

whenever we click the search button okay

so let's go ahead and let's see the

search button dude we give it an id

let's give it an id of search button

let's go back into our code

and uh

let's say

search

button is going to be

document.getelementbyid and we're going

to say search button and uh then we're

just simply just going to attach

a listener to this and we're going to

say

on click

get search

get search superhero and for now

let's just hard code batman so it should

just get us batman

and then

put him out so let's hit search

oh sorry let's hit run at the top first

then let's hit search and look at that

it's working perfectly exactly how we

wanted it to work and when i hit search

i am getting batman exactly like like i

expected

okay let's replace batman with thanos

and let's hit run and let's hit search

and you can see that i'm getting back

thanos

so this is good this is doing this is

doing what i needed to do all right now

what we need to do is we want to be able

to put in stuff in here and get access

to that so i'm gonna go

inside of this input

and to grab its value we're gonna give

it a name and we're gonna say the value

of this is

search input

so let's see if

that will allow us to do what we want to

do

so i'm going to go ahead and i'm going

to say const

search

input

i'm going to say document dot get

element by id

actually we have not given this an id

let's

take out the value

and we're just gonna do id for now id is

gonna be search

input okay let's let's do the id there

all right now i'm going to say

search input

and we'll try to get its inner text so

search input and let me let's see if we

do dot inner text if it actually gets us

what we want all right enter

enter text

and um let's console log it here so i'm

going to say console log

search input so every time i run i type

in that button so let's search

and it doesn't look like i got anything

let's type in hello

or let's not type in that let's say

cookie monster so it's like visible

let's put a cookie emoji in there and

let's hit search

and let's see if that did anything and

got us anything we're looking for

nope i don't see anything let's silence

our console logs here so i'm going to

silence that console log let's silence

this console log here and then

this one in here as well so no more

console logs let's hit run

let's hit search and something is

happening but we're not getting what we

want let's type it in search is still

empty all right so all we need to do

let's just hit run here okay all we need

to do is make sure search input is

documented element by d search input

right and then every single time we run

this function

search we're going to console.log

whatever value is in here okay so we're

going to say

search input

dot value and make sure the console log

this so now they'll extract the value

from that field so let's say i write in

uh

you know

cookie

monster and hit search and you can see

we're extracting cookie monster right

over here exactly how we want to right

so this is going to be the search that

we're now gonna pass in

okay so this is the search input.value

is essentially gonna be the name

so this getsearch superhero function

what we're gonna do is we're gonna copy

this search input.value and every time

we call this function instead of passing

hard coded thanos

instead we're just going to pass in the

user's

search input value that they put in so

let's try running this again okay let's

try running this again

and i will say thanos

and let's hit search and boom let's hit

batman and hit search and boom let's hit

spider

dash man let's go search

uh ethan maybe oh wow that worked i'm

surprised and that was fast too look at

how fast it is man

this is nice

right

um this app is doing what it's supposed

to be doing so when you search it gets

you a hero when you click get random

hero it gets you here as well now what

we want to do is above the hero it

should say their name okay and

underneath it just say maybe some of

their stats

so let's go ahead you should try see if

you could try that on your own

um

but we'll walk through it together if

you don't get it okay so i'll give you

five seconds to try to pause and try to

do that on your own

five

four three

two

one

cool so what we'll do is we'll

get the hero name i kind of showed that

at the top okay so let's see where we're

doing this we're saying okay the hero

image

i want you to replace it with an image

and i want you to replace it with the

following so let's go back

to where we're doing that

so we're getting the hero

let's just go to our random

hero function first because that one is

easier to understand

and here we're creating this

you know we're basically saying hey the

html is the inner html is this we're

creating this image show that image

well above that image we could actually

put the um

we could put their

name

okay so for example i could say

kant's

is uh we're gonna go grab the

json

and we're gonna say dot name

so json.name but we need to actually

like

make the actual h2 or whatever so let's

turn it into an h2 i'm going to say h2

wrap that in an h2 okay

and we'll

wrap this

this so json.name

and now if you want to like kind of

concatenate these together you could

actually go i mean this is kind of

getting really crazy

but what this is doing here is you're

inserting the name html and then you're

inserting the image right after that so

let's see if we can try this and if this

works

let's go random hero

right and now we get robin v

and the image let's try again we get

vision 2 and

boom

right we get the name

and the hero as well

and we can get their stats too so let's

try console logging the json

and we're gonna do dot power

stats

let's run random hero and you can see we

get back intelligence strength speed

durability power combat so you can

actually show all of those stats right

underneath here

see if you could do that by yourself

okay so here i would highly recommend

you take about five seconds see if you

could add that yourself so i'll give you

five seconds five

four

three

two

one

all right so let's go ahead and do this

together so i'm gonna say const

power stats um is going to be

you know not h2 but maybe it's gonna be

like

p tags

so we could actually either do all power

stats or what we can do is just do one

stat at a time so let's just try

intelligence and we're gonna put in a p

tag here

and i'm gonna say

dot json.powerstats.intel

and wrap that close that p tag right

there

so

so now what i can do is i can go and

take this intelligence and just show it

at the bottom right so

we can

add that right here

intelligence

hit enter and let's go right random hero

right ellie bishop intelligence is

undefined interesting let's see why

that's happening oh i misspelled

intelligence right here okay so careful

with the so that's why copy pasting is

oftentimes better better for programming

so you don't make these errors let's go

ahead random hero we got sauron

and then the and it's 88 over here okay

so

if you want to make that better you can

actually say intelligence

and then

it'll look cleaner that way so now let's

hit random hero

tundra intelligence is 38

and

try doing this

right let's make another one for another

stat so we're going to do instead of

intelligence maybe this one will do

strength

and we'll say strength

and we'll

paste strength right there

and then we'll attach strength onto this

so we're just making this this long html

right over here

all right let's run this

get random hero and you can see now we

have the cape we have intelligence and

strength

now if you want to make it like

kind of more enticing you for for

intelligence let's put a brain emoji for

this let's put a muscle emoji

and now let's run this get random hero

and you can see intelligence is 50 and

strength is 10. right random hero

intelligence is null so maybe this hero

does not have an intelligence right

here intelligence is 88 strength is 10.

now we can see the pattern here right

basically for all the stats we're going

to keep needing to repeat this pattern

again and again and again meaning this

it will basically you'll need to keep

copy pasting p tags together so at the

end of the day what it actually looks

like is p tag

right and then you're gonna have this

so like actually it'll actually look

like this so you have this p tag right

here

um combined with this p tag back to back

combined with probably another p tag

that talks about combat

right combined with another p tag that

talks about maybe strength or sorry not

strength but like speed followed by

another p tag that says durability

so we're seeing this like pattern here

and we want to actually create this big

long string and then we want to just

attach that string

right here so you know

it's a pattern so what we can actually

do is let's just create a function that

actually

you know gets

stats

get and show stats or actually let's say

get stats

html so it will

get the stats right but then convert

them into

a usable html so

we're going to create this function

and we're going to expect that we're

going to get a character okay so just

like we're going to we're going to

expect that we get this like json-like

data of that specific character and then

what we're gonna do

is we can do map here or we can do a for

each but but since we're just trying to

do a string concatenation it might make

more sense to do

a four

each you could also do a dot map and

kind of join everything together so

we could definitely do it

that way as well okay so how that might

look like is say you have an array

let me clear this

so say you have an array that says hello

by

cookie whatever

and let's give this so if i want to join

all of these i can actually just do this

and i can just say hey just join them

all together

so if i have an array

of like p tags

and i have

intelligence here

intelligence and then i have

another p tag

that says

speed

right i could actually do dot join here

and do this

and i just get back one big string

so this is kind of what we want to do

here so i'm going to say

character

okay dot map so map basically says

return an array

and

we're actually we're going to do power

stats

character.powerstats.map okay so we're

going to loop through all the power

stats

we're going to loop through all the

power stats

and for each stat

what i'm going to say

is

make this html

like looking thing here all right so

since what we're getting back is

actually an object it's not going to be

super simple to loop through this so

what we're going to say is

character.powerstats

is not an array okay this is actually

going to be an object that you're

getting back

so what we want to do here is we want to

loop kind of this way and i'm going to

say for stat in

character.powerstats and we're gonna

loop through this and let's just

console.log each stat

and let's call this function

getstats.html

uh

let's just say maybe

and i'll call this function and we'll

pass it the character which is just json

in this case

uh but this really is the character okay

so

get stats html pass it to character and

then it should just run

and then console log all the power stats

let's run this let's get a random hero

and you can see it just ran through and

says intelligence strength speed

durability power combat perfect

so now what we want to do now that we're

actually able to loop through this

now another way that we can actually

loop through this and let me show this

to you because this is kind of cool

so if you have an object

right so let's say we have things and

things is this object right over here

which has strength and cookie well i can

actually go and i can say

object.keys

and pass in things to it and it's going

to just turn that turn all of its keys

into an array and then i can actually

loop through those keys so

that's a really

cool way to actually

to actually like iterate so instead of

saying for stat and power.stats what i

could actually do is i could say object

dot keys

and um we could ask for the character

character the power stats

and this will turn the whole thing into

let's actually just

console log this so it's not super

confusing

i'll console log this here in the same

line all right let's run this and let's

get random hero

and you can see that i have this array

here intelligence strength speed

durability power combat so i just turned

this into

an array of all of the keys

so now what's cool about this is because

it is an array i can loop through it

with a dot map and then a dot map will

loop through this array and also return

an array

so now what i can say is for

each stat i want you to do the following

okay so

it's going to go through each stat so

intelligence strength speed durability

power combat blah blah

and here's what i want you to do you're

going to

uh create this string

okay we're going to say p tag and then

this p

make sure it's a template literal with

backticks it's going to be a p tag

it's going to have um that

the name of the key

that you're passing so here i'm just

going to say it's going to be the stat

okay whatever stat that is so it's so

this is going to turn into their

strength or whatever

uh or like

intelligence

right and then we can say

i'll put a colon here

right and then after that colon

we want to do is actually put the value

so i'm going to say

i'm going to say character dot power

stats

right and then pass it

that specific stat we're looking for so

i can just say stat or i could just do

it like this and i can say stat like

this

okay so

it's going to go to that object and it's

going to pull that specific stat so all

this means is let's say that this object

was called

we had something called character

dot power stats and that was equal to

this array right there whatever right or

that object let's copy that object and

let's say we have power stats is equal

to this object right here and so if i do

power stats

and i pass in strength oops it's going

to get me the value

of strength so it's going to get me 8

right there

so that's all we're doing here i'm

basically going into that object

and i'm just pulling out its value

and then we're just going to end this p

tag

and this p tag

all right so it's gonna loop through and

do that and then let's see if we need to

do anything else for this one

and honestly it doesn't really look like

it so we can actually just return this

array and it's gonna create a full array

okay and so i'm going to call this

const

let's say stats

and then we'll console log

stats

okay so let's run this let's do get

random hero and you can see now i have

intelligence and a p tag i have strength

and a p tag i have speed and a p tag

i have durability in a p tag power and

combat

and if we want to give each of these an

emoji we could do that as well and we

can kind of create a map for the emoji

and then

kind of like map the

map the stat

stat to emoji map we could create that

and then we could even use that here

and get the appropriate emoji so for

example

we can we can create that right here

right so we could say

stat to emoji

right and then we could say hey if the

stat is let's say intelligence

and you don't need to even put it into

string here

so let's go intelligence

is going to be this

brain

comma

and

strength is going to be muscle

and then we have speed

let's paste this and then we have

durability

durability

and then we have power

and then we have combat so strength is

that speed is a zap

durability is let's just say like maybe

a tire emoji or something we'd

apparently there's no tire so

say a rope

um

workout

lift there we go that's durability

and then power

i don't know that will be power okay and

then combat will be sword

okay stat to emoji

so that's emoji so here if we want to

actually like map that we could actually

just

right before this

stat to emoji and then give it the value

of the stat

and uh this is going to get us the emoji

that we want so let's run this let's hit

get random hero

and you can see like we have

intelligence as a brain strength is that

zap

boom

okay get random here another random hero

and you can see we got

boom right

power combat

our emojis are working kind of as

expected so this is actually making all

the stats for us and getting them

right

and

instead of having all of this crap right

here which is kind of like

weird and annoying i could actually just

remove this

right and um

and here we could just say con stats is

get stats html

right and then we could just replace all

of this

and paste

stats

and now when we run this and we get a

random hero

okay let's do a random hero

okay let's see it's all oh yeah it's

doing undefined right now and we know

why

because we haven't turned it into a

string yet we're like

this is still an array so remember at

the end of and we also need to return

we're not returning anything so we want

to do is we want to say

dot join like this okay and we want to

do return

stats.join

and like that

okay so let's run this and now when i do

random hero you can see that it's just

giving me one long string

of p tags intelligence is a p tag

this strength right here is a p tag

speed right here is a p tag and now when

i look

you can see that it's actually showing

up really nicely right so professor zoom

let's get random hero and you can see

all of this right here run this again

random hero

boom

mr freeze isis

run run run and then we're just getting

the intelligence strength speed

durability all of that right here

now it would be nice to have this

intelligence i capitalized as

capitalized as well

so let's go ahead and maybe add a um

dot title case 2.2 title case okay which

is kind of a nice little thing that you

could do

and we could actually pass that in

right over here and i could say that two

title case and let's see if

title case string method

javascript okay so you can always like

google this stuff too and i'll kind of

show you examples

and let's see if there's a method that

does title casing

do we have to oh dot two upper okay so

we could actually just do that to

uppercase and we should be

we should be fine that shouldn't be too

bad or maybe that just uppercases

everything that's not what we want

either

actually we can just do two uppercase

and yes it's not title casing because

title casing is like pretty complex but

dot to uppercase is a method that comes

built into javascript and you can see

what it does and it's really nice right

it just capitalizes

everything which is nice like we're

capitalizing the stat right here um and

you know that makes that makes the whole

thing just look a lot better so the

stats html function yeah it's getting

definitely pretty intense i can feel

that but uh you know if you're doing

this and you

you know you got up to this part like

you're doing a good job so just hang in

there and honestly what we could do is

we could probably turn this function get

stats html into like

get

hero info

you know get hero info html or something

because we can just create the whole

the entire html in that function which

will be really nice we just hand over

all the html elements so it's like the

hero name right

well that's just character.name so for

example if i copied this and i brought

it down here

this is this would just become character

dot name so that should take care of

that

and then we actually update the div at

the end and we create we do this like

image thing right here

so this image thing that we're doing

here

well that would be really nice to

actually do it handle that here as well

okay so let's try handling that here i'm

gonna say character.json

image url okay this will be a template

literal like this

just a const

image so this will be the image uh html

okay and then we have this final html

that like yeah and then here we go ahead

and we um

update this so yeah get stats

so we can actually rename this function

as to show stats because really what

this function is doing is showing the

stats on the screen

um or showing the

hero info on the screen so we could

right click this and rename all

occurrences we could say show

hero info

it's a show hero info so this is

basically the function that's actually

going to show this here the info

so i think that's like probably a much

better name for it and then it would

make sense if that's the function that

actually updates

uh the entire app as well so i'm going

to copy this for now we're going to come

down here and i'm going to paste this

right over here

so this function doesn't even need to

actually return this return anything

stats

boom

and in so for stats we can actually just

do the dot join right here so i can

actually just say that join so then it

it just turns this entire thing into

that long string instead of keeping it

as an array

and then this hero image div dot inner

html well this just becomes something

simple

we can actually even remove this guy now

and actually just say

image

so this just becomes this nice little

html so we get we make the name html we

make the image html

and then we make the stats.html

and then we just concatenate all of

those together and update the hero image

we don't need to we don't need this

function to return anything right show

hero info

and we basically get rid of all of this

all of this here

and we can just simply call the show

hero info function so now this function

just became really easy to look at right

get superhero

once you get the superhero

you just pass that superhero

jace uh con superhero is equal to json

you just pass that

hero or that character or whatever

and that this just shows it on the

screen so let's actually try this let's

run this let's say random hero all right

so it didn't it's not coming up on the

screen let's figure that out real quick

so what i'm going to do is i'm just

going to say console.log

and let's see if uh name is working as

expected so let's try name

let's run random hero yep oh actually

it's working i just had to like hit the

run i just think i never hit run

now let's hit random hero and look at

that random here is showing up

right and then intelligence strength

speed durability all of that showing up

exactly how we want let me remove

all of this here

so now it's really easy to read get the

superhero

show the superhero that's it now this

function is reusable and i'm gonna give

you that as an exercise so try that

right now

see if you could take this

what we did right here and add that to

search functionality so when i type in

batman and i hit search

make it so it actually shows me the

batman name it shows me the batman image

and it shows me the batman stats so see

if you could do that on your own

i'll give you a hint it's you're pretty

much only going to be writing it's going

to be just a few lines of code and it'll

do the entire thing for you so i'll give

you about five seconds see if you could

try to figure out i mean pause the video

and see if you could try to figure it

out five four

three

two

one

okay let's go ahead and do this together

now so this is going to be really really

really really nice okay because watch

what we're gonna do

let's go to our search superhero

function

and i'm gonna delete everything from

here

okay and remove everything

right and we already have our hero here

which is the first item

i'm just gonna call our show hero info

and i'm gonna pass in the hero that we

have

okay and let's give it a try now so

let's search

uh batman

and let's hit search

and look at that it's already working

right this is kind of

pretty unbelievable but if you actually

open this app up

and you go batman and you hit search

boom

let's go spider-man

boom let's go thanos

boom

[Music]

i mean this is amazing or you could get

a random hero and both them both of them

work so just to explain a little bit

about how we were able to make it work

that easily is look we already have

access to the hero right here so then

you just pass that hero to show hero

info and it knows what to do already

it knows that it's going to get a

character it knows it can do

character.name it knows how to get the

image url it knows how to like

turn the thing into

object.keys map through it get the stats

you know get all of these nice emojis

that we have here it knows how to do all

of that

and so then it just kind of

does all of that for you and then you're

you're good you're just essentially

reusing a function that you've created

that's the nice thing about reusing

functions right

um

it it like really is a game changer when

you can reuse like your existing

functions

all right cool so now just to kind of

make our app pretty i'll just say like

um at the top

kind of like right here and i'll say

um

[Music]

you know

[Music]

superhero app

and then

for instructions we'll just say like

you can search for a superhero like

batman

or thanos

or

simply

hit

all right so superhero app you can

search for a superhero like batman or

thanos or you can generate a random hero

so now the user goes to this app they

understand kind of how it works and what

it means so hit random hero

all right let's open this up here

superhero app you can search for a

superhero

or you can generate a random hero so

let's try random hero

right boom we're pulling random heroes

and this is like going to an api pulling

the data from there or i can actually

say you know bane let's see if that

works

you know thanos i know that works ooh

bane has nice combat

why is this power like only 51 do we

have superman here

oh cyborg superman that is badass

durability 100

power 100 speed 93 strength

i mean yeah but i don't really like

superman because he's just overpowered

it's like oh he just has like literally

every power on the planet it's like

how's that a fun superhero

i need my superheroes to kind of be like

weak but then use intelligence and

that's pretty cool

um or maybe that's how i was because i

went to chess club

and i resonate with those heroes more so

there you go we got this app it's fully

working

it's doing everything that it needs to

do now what i'm going to do is i'm going

to move it over for you inside of our

javascript course so you have access to

this under api

i'm going to create a new folder and

this is going to be called superhero

superhero app or whatever

and in here we're going to have a

index.html

and you don't need to follow along on

this one i'm just creating this for you

so you you know that this is available

to you and so we're gonna paste the

index.html in here we'll go here copy

the script so command a command c or

ctrl a control c

and you're gonna paste that in here

and then i'm just going to link it all

right so now you should actually be able

to go to the home page here

and you're actually going to see

get super heroes right over here

right and you'll be able to click in to

get superheroes

and then the app should show up here so

you could do random here and it'll

generate a random hero

or you could ask for

thanos

and search

and it'll bring up thanos for you okay

and if you want to make this app a

little bit more robust meaning like

well actually i think if you tried

thanos let's see if that works

search oh that still works so that's

pretty cool

spider

man

let's try

okay so the app is actually smart it can

it can detect that normally what you do

is you call dot to lower case on this so

then like whatever user types it just

lowercases it and then you do whatever

you want with it but this is fine

so there you go your app should be

working here and should be available to

you

in your javascript course you'll be

you'll be able to click it and see how

it functions and uh this will be the

solution file for you okay so the

solution will be available for you here

and you can just kind of go and play

around with it and use it or for bonus

points you could replace this with your

own code okay so if you want to be real

pro go ahead and copy paste your own

code that you just did in the other

repel right paste it over it and

see if this still works and if it does

you're a real champ because i want you

to have this entire javascript course

should essentially turn into all your

code everywhere here okay so we've

covered a lot

i hope that you've enjoyed it so far i

mean this was a lot of fun covering apis

in so much detail and building a mini

project

i'll see you soon

i promise

you will be great i promise you're going

to be a champion developer one day and i

promise i'm going to teach you promises

let's get right into it

so promises are

kind of tricky to understand it throws

people off a lot but you and i are going

to learn it together just go to

replay.com make sure you're here

replay.com this is the url and then

we're just going to open up a new rupple

with html css javascript and let's just

say learning

promises okay and hit create rubble

so we're just going to kind of start

from scratch

and

we're going to walk through kind of

real real basics of promises okay so

promises introduces the concept of

asynchronous programming all right it's

a complicated word

and i know we've talked a little bit

about promises already but now we're

gonna start deep diving into promises

and looking at it at like bare bones

basics and starting from there so

asynchronous programming is some piece

of code that's going to run out of order

okay it's going to happen at a random

time so the way that i want you to kind

of think about it is like this like

imagine you're at a restaurant and you

order some food at the restaurant now

when you order that food you're still

continuing your conversation with

whoever you're sitting and eating food

with while that food is being prepared

you're still talking once the food is

prepared the server will bring it up to

you or the server will say hey no soup

today right that's what they'll tell you

so let's go ahead and mimic that type of

that type of

thing but inside of code

okay so i'm going to go ahead and zoom

in here so you can actually see a lot

more clearly let's do it like this

all right and let's say that you're the

server or let's say that there is a

server

and you're going to

you order

let's say tomato soup tomato soup

meanwhile

you continue your converse convo with a

friend

so your life basically continues so this

is your other code running whichever

code is ready to kind of go

and then once this uh

your tomato soup is done

your server

brings it to you

in this case we'll just say

if your problem is resolved okay the the

order that you requested if your order

is resolved then your server will bring

soup your server brings you

soup

okay if it is not whoops if it's not

resolved

paste

what's going to happen

is

rejected okay so this is other situation

that can happen and your server will

tell you like

no soup today okay so maybe like these

are the two things that can happen

either you get soup or your server comes

in to you and tells you hey

no soup today so these are the two

different type of scenarios that can

happen now in code

we're going to try to go ahead and mimic

that and kind of write it but first

things first i want to teach you how to

write asynchronous code right so

if you've ever done a fetch request or

api request that's an example of

asynchronous code the way to mimic that

is usually you're waiting for something

to come back to you so the way we can

actually mimic that is

we can write a set timeout function and

what this does is it takes in a function

so let's say

whatever soup okay and just console

let's just console log soup for now

console log soup and we'll pass it 2000

milliseconds now what this means is

this function is gonna

wait for two seconds and then it's gonna

say soup so let's go one

two

and boom we got soup okay let's run it

again one

two

soup

so every single time two seconds happen

you get soup so two thousand

milliseconds is one second

one second

okay and so in other words what you can

say is if you have a function

okay so let's just say you have some

funk

and this function that you have it like

kind of prints out soup or whatever

you can just pass in your funk like this

let's call it waiting for soup paste it

in here

run it and this code is basically saying

hey set timeout

you're gonna you're gonna run this piece

of code aka this over here and i want

you to wait two seconds oh sorry this is

two seconds sorry two thousand

milliseconds is two seconds

one thousand milliseconds is one second

okay

uh my apologies on that

so you say hey i'm gonna wait for some

soup and two seconds i want you to print

that out so run i'm gonna wait one

second two seconds and then boom i get

soup let's run it again one

two

and i get soup

one two

and i get soup

now let's say you have other bits of

code so let's say you have some code

which is console log

you know you you get to the restaurant

with your date

and so you

start the convo with your

date right whoever that is you start the

convo

and then

you continue the convo right but now

this is the interesting that happens

right so watch this for example

and i'm going to take this

and paste it here

so

on line 10 you start the convo and line

12

is you it's gonna say still speaking so

what should happen well what you would

imagine to happen is i'm going to

what what i'm what you should imagine to

happen is this line runs first then this

line runs second and then this line

should run third

but watch what's gonna happen you start

the convo with your girlfriend or your

boyfriend whoever

and it says still speaking and then you

get soup that's really weird right so if

i just go and do this and make it really

clear this is one

this will print out two because this

goes in right here and this should be

three so you should you should expect to

see one two three but watch what happens

one and three run first and then two

comes out so it seems like if i had to

order this

it seems like this line of code seems

like this line of code

runs first and then this line of code

runs second and this line of code runs

third because this we're waiting for

this all right this is like kind of

running in the background now let's

model this in a more realistic way so in

the start you start your convo right you

sit down and start your convo and then

what we'll actually say is let's call it

order soup

so you sit down you start the

conversation

with your partner

line 11 you order your soup and then

you're still speaking right you continue

speaking so let's run this

you sit down you order your soup then

you wait a couple of seconds and then

soup is ready in reality of course the

soup is going to take longer than two

seconds to get ready but this is just to

show you that you can start a request

right right on this line is where you

basically start your request

and then

your request is ready at a point some at

some point later right you get the data

back

now when you're dealing with stuff like

this with timeout yes you will get back

you know kind of what you're looking for

but timeout is also not really good it's

called it's thread blocking meaning like

it will kind of stop you from often

times doing other things

so when you're dealing with real world

data like an api request it's going to

return it to you as a promise what

you're not going to get back

is this timeout thing okay

so let's go ahead and kind of model that

so let's create our first promise

so i'm going to basically go ahead and

say

const promise one

and it's gonna be a new promise okay and

this is a promise class we'll talk a lot

about classes don't worry if we haven't

already you know in in the javascript

course if you're watching it in the

javascript course there's gonna be a

timestamp for promises or if i have it

as a video on our youtube channel or

sorry not promises with classes go ahead

and watch that watch the part with the

classes because you'll then really get

how

like a promise works under the hood

because whenever you do new you're

actually creating um

like a

object from a class

okay so anyway

so promise takes in a function and that

function takes in two things it either

takes in a or a reject

and then it wants you to do something

with it okay so now what i'm going to do

is i'm going to say

set timeout

set timeout will take a function and

let's just say i'm going to

do this

and it says soup is ready

all right and i'll do the same thing

i'll wait two seconds

and then

what this code will do

is write actually inside of this timeout

let's go ahead and do this right inside

of this timeout so i'm going to do the

following so we're going to have a

timeout function

and inside of this timeout we're going

to say is ready and for now we'll set is

ready to true

so we're going to say hey if the soup is

ready and this is how you do ternary

operators by the way so i'll show you an

example of a ternary operator so if

let's say you have a

if

is ready equal equal true

then you know run this

um else

do this

all right so if you have this line of

code you could write it in different

ways the first thing you can do is

actually you can remove this because

if this is already true then you don't

even need to say equal equal true but if

you want to leave it here you can that's

not really going to change anything

and then what you could do is you could

turn it into a ternary operator as well

so you could say hey you could remove

this

and you could do if this is true do this

if it's false do this so that's what

we're doing here on line 20. we're

basically going to say hey if

is ready is true then i want you to do

hit

you know soup is ready

otherwise what i want you to do

this is where our function ends

right and then let's give it two

thousand second millisecond wait right

here otherwise i'm gonna say no soup

today okay so let's just say

no soup today

something like that

and i'll put a little check mark here

if you don't have emojis by the way you

can get this app called rocket on your

macbook

all right so now what this is going to

do is it's going to run and what i want

to do is instead of console.log for

promises what we do is we actually will

do resolve

or reject

all right so if uh like if it's a

right scenario and you want and it did

it correctly then you want to say

resolve like so if you did if you made a

let's say a api request and you got data

back you want to resolve that and return

it

if you didn't get data back for whatever

reason maybe there's a server error

maybe the data wasn't ready then you

want to reject it so in this case we're

going to say go ahead and reject no sub

today okay

so do this and this is going to be our

like first

promise that we have uh wrote

and i'll remove all of this

okay so remember

this is to just kind of visually explain

it to you how ternary operators work is

like this

okay so it's right here right

this part right here

is the condition

this part right here runs

if you have a true runs if true

and this part right here

runs if false

okay that's how

that's how ternary operators work okay

so if i put a box around this

the term for this

if you haven't seen this yet it's called

ternary

operators

so instead of if else condition you'll

have this like

more specifically it's that like

question mark part

and the colon here

okay cool so i have this promise here

and now let's see what happens when a

console log this promise so let's see

what happens

promise one

and i'm gonna go ahead and run this

and notice what i get back so i'll

comment out all of these lines here

up at the top

let's run this and you notice i actually

get back uh something called a promise

so wait how is that useful

i did this and i'm just getting back

something that says promise what the

heck does that mean

all that's saying is hey you have a

promise but that promise has not been

fulfilled yet it just started so it

started and like i'm just letting you

know that it started now i need to tell

it to do something once it's resolved so

remember it takes two seconds to resolve

but when i run this it instantly does

promise right

so what i want to do is i want to do a

dot then

and dot then is the special things that

a promise has

and what that does is if the promise

resolves

then you can call a dot then and get its

value so we can say

console log value like this okay and

let's run this and you're gonna see

first it says promise and then after two

seconds it says soup is ready if i make

this five seconds so it waits that'll

make it even more obvious so it just

started and it said promise now after

five seconds one two three four five

boom

soup is ready and it shows up

so you can see that this is working kind

of the way that we you know expected but

this dot then notation for you might be

weird but if you have done api requests

you'll recall

that

hey this is that's actually very similar

to api requests because that's where you

use the dot then thing and that's how

you actually pull the value out

now

what happens if the soup isn't ready so

i'm going to go on line 19 and i'm going

to change that to false what happens

when the soup is not ready

well watch what happens we're going to

wait five seconds one two three four

five

and nothing happened

what i don't see anything why did that

happen that is weird

it's because we're not actually

catching that mistake okay so let's go

right here

this is all gonna be one line but i'm

breaking it up into multiple different

lines so you can clearly see like what's

actually happening

okay

um and so i'm gonna say hey

get me the value on success so the dot

then is when success happens

okay and then there's a dot catch

so this is when an error happens

okay and so i'm gonna say

get me the value in this case

and let's run it

so

watch what happens in five seconds one

two three four five and boom no soup

today and that's happening because our

on catch is actually catching

the reject so whenever you have a reject

like this

that goes into catch

and you can actually pull that from the

value

so

let's go ahead and do

i'll say error

okay

and we'll just make it an object

error

error

and here we'll say success message and

i'll say success and an object like this

so we'll run this and now you'll see

this promise will run and then in five

seconds it will get get you

okay so in this case here it said error

no soup today okay

and what we'll do is we'll make this

function two seconds and what i want to

do here is instead of false or true i

want it to randomly select true or false

so i'm going to put true or false i'm

going to make an array and then we're

going to index that array if we index it

by zero we're going to get false if we

index it by one then we're going to get

true what i actually want to do here is

i want to index it

by something random right so i'm going

to say math.random

and then i'm going to

let's actually call math.floor

math.floor

and in that i'm going to say math.random

and we're going to multiply it by 2.

okay

so

this piece of code here will always make

sure i either get a 0 or a 1. that's all

that piece of code is doing

so this way i'll pick a random true or

false and so that way it'll randomly

either

resolve or reject

and i'm kind of mimicking a real

situation here

fifty percent chance it'll work fifty

percent chance it won't but that's not

how good apis are right good apis work

99.999 percent of the time and there is

this tiny bit of time where they break

or return some kind of error so

that would be a terrible api if it

worked only 50 of the time

so let's run it

and boom on success we got soup is ready

okay let's run it again

we'll wait two seconds

and we got nothing so what happened here

we might we must have had

a weird error oh no it just took longer

than two seconds apparently and then

boom error no soup today

right and i can keep running this and

it'll randomly keep selecting and then

it'll just check hey if it's ready is

true run this and if it's false

it will run the next statement right

because all it's doing here is putting

either a true right if i put a true here

and i run

you'll see that i'll always get and

let's make the wait one second so we

don't have to wait that much

so if i say true it's always going to

give me back success

and i can run it a million times and if

i hardcode false here you'll see that

it'll always give me back error

so we're just going to put israeli here

because israeli is either going to be

true or false

okay great

so now you can see

how our promise is working

and this promise is extremely similar

to the promise that

we had in our

you know the dog application we made and

the superhero application we made and

actually let's go ahead and reference

that

so

so go let's go back to our javascript

course and if we go to

uh dog random and we look at the script

right

notice

that we're doing something very similar

here right we have this fetch request

and let's actually bring that in here so

we can actually play with it

so i'll run this and watch what happens

okay

and i'll console log this for you

console.log and you'll see that'll

actually say it's a promise

and to make it visible that i'm console

logging this i'm just going to say fetch

like that

do it run

and you can see that it's telling me

that hey the fetch promise has began it

has started but now i actually need to

do something with it so what i actually

need to do in this case is i want to do

let's do

let's do this

okay so i'm going to do fetch

and then on another line so like

normally i want to do this but you see

how the line is running so long that

it's going to be too long so i'm going

to break it up onto a new line so i'll

hit enter

so we're going to say fetch dot

then

and i'm going to get the response

and we're going to get the json response

back now here's the interesting part if

i console log

this part here you're going to notice

that this actually

is also a promise so let's console log

this part and i'll just say

response

and we'll run it

and notice that response is a promise

response json is a promise too

so when you run this call majority of

the times you're sending another request

and saying hey can you please turn it

into a json and then that is also an

asynchronous task that could take

multiple seconds before returning so

it's kind of like this invisible coding

that you're doing here right so

we have the fetch promise once it's once

it resolves

once the fetch promise resolves

i want you to

run the response promise with the json

and guess what guess what you're gonna

have to do in order to pull a value from

that

promise

you're gonna have to chain it with

another dot then okay so we're gonna

have to go and chain it with another dot

dense i'm gonna go down here

and we're gonna say another dot then

and we're gonna say data or json or

whatever

you're gonna say console log

data okay this this variable here does

not matter you can call it whatever you

want and if you ever hear that that's

just me using a focus app to keep me

focused to keep shooting this so if you

ever hear that i apologize it'll happen

every

20 30 minutes or something like that

just ignore it

all right let's run this

okay so what did we get

we got oh yeah

we gotta do not console log

all right so make sure to remove that

console log that we had remove this part

right here

and just return response.json like this

and then do data and call data on this

so let's run that

and now you can see that we actually got

back

the random dog image that we're looking

for okay so when you're doing fetch

remember

fetch is a promise

and then you do the dot then

response and then that's also a promise

okay so this is a promise

that's a promise okay so there's like

everything is a promise

all right and then within here within

right here

you you have access to the actual data

right there you actually get the real

real real data and you can do something

with it okay so that's why

that's like a little bit of a funny

reason why that happens but but

underneath the hood it's a promise

now i'm going to teach you something

that's going to make your life a lot

easier moving forward

and it'll also help you avoid having to

do dot dance and dot catches because

they get pretty annoying as you can see

you'll have to keep chaining and this is

essentially one line of code right if i

actually remove the wrapping or whatever

like this is not how you want to be

writing your code honestly with like

that many.then.then.then.catch

because then you'll have to attach dot

catch they'll catch any errors that

happen

and honestly it becomes kind of a

nightmare and so

what you want to do

is you want to avoid using this syntax

and you want to use the new syntactical

sugar that like es6 and beyond provided

for us and that will make our life

incredibly incredibly easier

and so i want to introduce you to you

the concept of

async await okay it's incredibly easy

it's not hard

it

will make this part a lot easier it'll

seem a little foreign and weird the

first time you look at it but once you

get used to it that's the way to go and

your code and your logic is going to

become a lot easier okay

so

this fetch request that we're doing here

right

we want to avoid all these dot dens and

make it simpler so let's create a new

function

and we're going to say get get dog

whatever and now what we're going to say

this is the most important part is

whenever you want to use

a weight

you're going to need to use async

okay so make sure so what we're going to

do is

just pass in the async keyword here

which just says hey this is an

asynchronous function so this function

uh will run out of order if this

function will need to communicate to the

internet or get some type of data or

we'll need to wait uh half a second a

millisecond a couple of seconds to get

this data async just means whenever you

have to like

speak to some website or some database

or something

you're using an asynchronous function

there like 99.9 okay so

whenever you think api requests think

async whenever you think i'm going to do

a fetch request think async functions

whenever you have a post request

async function

all right so i have this async function

over here

now with this async function um what i

want to do is i want to say

fetch

response is

and i'm going to fetch this image okay

the only special thing that we're

actually going to do here

is since this url run real

url runs really long i'm just going to

say const url and pass that in so we

could just actually say url

and then i don't need to make this this

huge we can make this much smaller i can

make this bigger here

so i have my url and i'm just going to

fetch that url and then what i'm going

to do

is i'm going to

get the data

and here here's the interesting part so

for this what you want to do is you want

to pass in this keyword a weight all

right this is very important a weight a

weight is the same thing

as you

doing

dot then

and then saying respond something okay a

weight will make your life a lot easier

so we're going to say oh wait then next

line

i'm going to say const data and i'm

gonna say

await

response.json

so look at that we have our fetch

requests and then we have our

response.json

and that's being stored inside of data

and now you can use the data variable

kind of anywhere you want inside of this

function it'll work

everywhere and it'll work normally and

then you don't have to like you're not

forced you're not forced to like code

inside of this then

method like that's kind of ugly and

annoying

and now you could use

console log data

so let's try this and run it okay and

you can see that

um i got back my oh actually sorry we

didn't call this function yet that's why

i was like this was something weird is

happening all right let's run this

and you can see that we're now getting

our our random dog

right over here okay i'll comment out

this fetch right here

let's run it again and you can see that

i'm actually getting back my dog so this

syntax is

really really really clean it's a much

much much better syntax so in order to

use this you have to create a function

you cannot use so here are the rules

rules for using

async

await

one

you must

create a function

okay you cannot use async outside of a

function it won't work so you can't like

do this here or something like that that

it won't work like that so you need to

have a function

all right you can't like use a weight

like this

you need a function that's called async

and then you can do all your jiggery

pokery all right that's step one

two

you

must

use

must create

um let's use

keyword

async

use the word

await

so anything you're waiting for you just

await it right so here we're gonna await

this promise and then we're gonna await

the second promise

and that's it those are the only two

promises right this is a promise

and then this is a promise and then once

you are done waiting for them

you just get back the actual data and

then you can do whatever you want with

it right so that data gets stored here

it's a much much much nicer way to write

it so try to do it like that now

i'll give you a little exercise

see if you could do this soup example

that we just did see if you could do

this

but using async await for this promise

right here rather than the dot dance

okay so see if you create a function

let's you can call it whatever you want

like get soup or something right and

then see if you could turn this piece of

code

into

this

all right so take like five seconds give

that a try so i'll give you five seconds

five

four

three

two

one

all right if you haven't paused it

or you pause it whichever one hopefully

you gave it a try let's go ahead and now

do this together okay so i'm going to

say const get

soup

and we'll do this way and then here i'm

just going to say

const

soup is a weight

promise

and then we can probably console log

soup and let's see if this works okay so

get soup and i'm gonna run this

see i ran into that problem myself i

forgot to put i mean and what's nice is

that it actually gives us a nice error a

weight is only valid in async functions

and at the top level body of modules so

let's go ahead and put async

and run this so boom there we go error

no soup today right if i remove a weight

watch what's going to happen and if i

run this it's just going to say promise

right here i'm not going to get anything

else i'm going to comment at every other

console log statement so we don't get

confused

that's it it just says promise and then

that's kind of it but the only way to

get the data out of it

is you just say oh wait

and now that same thing that was

initially saying promise

now we'll actually return you

data

okay i don't know why it's taking that

long why is it taking forever okay there

we go soup is ready perfect let's run it

again and let's see what it says this

time soup is ready let's run it again

mmm

so that's weird how come sometimes it

says when the soup is if i run it if

soup is ready

you know it says it correctly but if

soup is not ready it returns nothing

isn't that a little sus what's going on

so what's going on is now you have to

try catch this

so

if you get an error

you're not doing it you're not able to

do a dot catch like how you were before

so that's what's happening we're getting

in a reject reject and reject is not

going to get stored in here so what you

want to do is you want to say try and

you want to wrap this in a try catch so

what i can do is i can say try

and we try this and we console log

and then we do catch

okay and we just let's just say console

log soup and let's see what happens soup

is ready let's run it again

soup is ready okay so see we got

something that was an error interesting

so maybe let's pass in

let's catch the error here and let's see

if we can print the error out so let's

run it and let's hope we run into an

error and let's see if it actually

prints out our error or not okay soup is

ready soup is ready

boom there we go no soup today so if you

want to catch

this is how you catch with async awaits

in tax

so the catching is not the prettiest

but i will just promise you this that if

you start using async await a weight

will make your life

a lot simpler and they'll simplify your

code a lot and then

it'll be much easier for you to deal

with things when you're doing

asynchronous programming so a weight is

really

like the way to go

all right now what if we want to take

this example further meaning

if you promise the waiter or the waiter

promises you that they're going to bring

you soup well if they bring you soup

then that's good now what how can we

take this even further if the waiter

brings you soup then maybe you also

pay the waiter okay so let's let's write

these up here

so if waiter brings you soup

maybe then you tip the waiter

and you

you pay for soup

on the other hand if you don't get your

soup so this is like what happens if the

situation is resolved

but if it's rejected and it doesn't go

through and your soup is declined for

whatever reason or they didn't have soup

then maybe you

you know you're you're a crappy customer

and you leave a bad review

and uh you give no tip all right so how

are you going to actually

you know

write that in code so see if you could

give that a try and see if you could

take this

or the dot down one farther

and see if you can kind of um

add in all of this sauce like in terms

of

adding in a bunch of these things okay

and just you could create arbitrary

variables like

uh tip for the waiter so you could

create a variable called tip you could

create a variable called pay and you can

just kind of set what happens to that

but the main thing i'm looking for is

you know

where to write those lines of code okay

that's mainly what i'm looking for

so give that a give that a try and then

we're going to do this together so i'll

give you about five seconds so go five

four

three

two

one

all right let's do this together now

so i have this

you know so we have either whether it's

resolved or rejected now everything

that's resolved in my mind is going to

go inside of this try block and

everything that's rejected is going to

go inside of this catch block right so

say we have

you know cons and and maybe we can give

a ra rating you know why not so let's

say we have

let rating

we define another variable

let tip and we define another variable

let pay okay

and if

this if we got our soup as promised

well then what i'm going to do is i'm

going to say i'm going to increase the

rating to say i'm going to say hit i'm

going to rate this place five stars

and i'm going to

say the tip is

you know maybe 20

and i'm gonna pay

you know ten dollars or whatever for the

food and then on the other hand

if the and then for review maybe i give

a five star review here right

but on the other hand if i don't get

what i want

then i'm going to leave a rating of one

star

i'm going to leave no tip

i'm not going to pay anything because

while i didn't get anything and then

review i'm going to leave one star

okay so we can kind of do that

and what we could do is actually we can

even turn this into an object i'm

thinking something let's do that

actually

uh const

data okay let's just say data because

that's how usually

you get data

rating is zero and tip is zero and p is

i'm just gonna say zero i mean it should

be kind of null okay because those are

data types as well null and undefined

so

you could do null or undefined if you

want to be like really accurate because

these aren't defined yet actually

all right so pay is zero and review is

zero and let's actually use those data

types afterwards and i'm gonna remove

this

and then

we're just gonna say

data.rating data.tip data.pay

data.review and then we're going to do

the same thing here

so now it's actually even looking kind

of like a real api

which is interesting

and then at the end of all of this

whichever one we're going to return data

and return data

okay the try catch block

so now if i do soup and i'll do console

[Music]

log

now let's run it

and watch what's going to happen so

promise is running soup is ready

all right why didn't we get our data

why did we not get

our data let's see every console logging

it we are

are we running yeah we're running at

soup interesting

yes this is the magic of

uh asynchronous information right that's

the problem with it so i can get caught

up but i can get caught off guard with

it too even though i've been programming

for years so it is complicated

see here if i actually run this it's not

going to work because this function runs

instantly

and then i'm sitting there and waiting

for the data so i actually have to await

this data and get the results back

because it's a promise and i need to

retrieve the data but i can't just await

it right so i have to actually

so what i need to do is this

say i want to remove this console log on

line 47 and i still want it to actually

read the console what i want to what i

want to do is get soup right i want to

actually call

this is a promise getsu is a promise

right and it returns when we run

asynchronous function it's going to

return

uh return a promise okay so in order to

get this function we can't just call it

right when you just try to call it it's

not really going to do anything so what

i want to do instead

is i want to do dot then and i'm going

to say

value and we'll console log the value

that we get out of it

let's run this now and now you can see

the soup is ready and we got this data

so we're go we're actually got the data

back that we were looking for

right and then here i can actually see

that the rating is five tip is twenty

percent pay is ten dollars reviews five

stars if i run this again

and oh no soup today well guess what

rating is one tip is zero pay is zero

and review is one star

so that's how

that's how this works hopefully like

this makes sense for you on

you know kind of

how this

how you actually do this how all of this

works

so here's a simple trick for you to

remember if you're struggling with

promises or you've ever struggled with

promises or i promise you will struggle

with promises you know in the future

if you ever so let's just do this okay

so

see say if you console log get soup and

you're like how the hell do i get the

value out of this why can't i extract

the value out of it

if you ever read that something says

promise there's only

two ways to ever extract the actual

value out of this it's only two ways

either you await it

which you're going to need to wrap that

in a function that has async

you're either going to need to await

this

or

you're going to need to

dodge then this all right and then just

do

value

value right return the value

so those are the only two ways you

actually get data back from an async

function

or any type of asynchronous task or

asynchronous promise even if you make a

sum function and let's say you make a

async sum function

that takes in two values a comma b and

returns their sum a plus b

if you call this function right watch

what's gonna happen

so if i call this function i pass it one

comma two and then let's just say sum

here and i'll run this

even if it's something simple like this

watch what's gonna happen when i run it

i ain't got back the results son what

the hell why not get back the result i

clearly defined this there isn't even

any asynchronous parts to this i'm just

clearly saying sum up a plus b why are

you playing games with me

but because we have the async keyword

it's an asynchronous function which

means by default it returns as a promise

so the only way to extract the value out

of this you give it a try i'll give you

five seconds five and you can pause the

video five four three two one

only two ways either you call a weight

or

async my friend so

let's go ahead and do async here

uh or sorry either await or dot then so

let's do then and we'll say console.log

or sorry we'll say value

console.log

value just like this and now let's run

it and you're gonna see that we got back

to three

that three we extracted right away so

that's how async functions work

and

any type of async stuff that you have if

you want to extract its value you're

gonna have to start using

dot thens to retrieve value for them

especially if they return data like this

all right so hopefully

that gave you some examples of how this

works

all right

this probably isn't going to solve

everything for you but it's going to

give you examples and what we're going

to do is in notes here in your

javascript course that you're going

through right now

in notes i'm going to create a file and

i'm just going to call it async

let's call it promises async awaits it

apis whatever okay and uh let's uh

let me call it dot json dot js

and i'll paste in all these kind of

notes for you as reference point

so you don't lose them so if you want to

go in notes you can look at it okay

and then here's another note for you

that lance has created these are really

nice and really helpful it kind of goes

through some of what we've talked about

and plus it asks you lots of questions

and gives you lots of written notes for

promises to practice them more and to

really understand them more right so he

walks you through hey how do you get the

promise variable how do you increment

the waiter money

how do you

you know how do you do the async await

plus try catch

he has an example that's like an actual

working example and if you want to run

any of these examples open up a new

rupple copy paste copy this code paste

it in there and it'll work

and how to actually get this data okay

so here we're doing return user and just

remember since this is an async function

you're gonna have to actually extract

its value out of it

so we have those

exercises those notes

here for you if you want to get more

practice with the javascript course if

you're not in this javascript course or

whatever make sure you're watching this

on youtube just type in javascript

and

you should find this all right so with

that said i hope you enjoyed this i hope

you learned something about

promises

and i know it's confusing but if you

really

stick to it and keep practicing you'll

keep getting better with proc

with promises

and

if you can just really work hard and

understand this concept of promises now

your journey to becoming a developer

will become

much much much easier because there are

so many

concepts that are asynchronous when it

comes to web development

and non-understanding promises will

always get you in a lot of trouble

all right with that said i hope you

enjoyed this and one last thing i i said

i was going to talk about null and

undefined you could make these like

you know null types because

if you didn't give a review it should

really be type null

right

and uh let's just say we don't define

any values there and if i run this i

should get back like null types

if uh you know my soup is order right no

no no no

okay which which makes sense because by

default

why would you give a rating of zero by

default right that doesn't make sense

that would mean you literally go to a

restaurant rated zero you actually paid

zero but you haven't been to that

restaurant so it's actually null it's

not it's non-existent or undefined

either

you can use either one of those and

that'll represent a similar thing in

this scenario so null is a special value

and undefined is usually also a special

value

all right with that said i hope you

enjoyed this let's keep on going let's

keep on learning

all right let's take your api skills up

a notch we're going to build this

weather app right over here i can type

in arizona

hit search

temperature is 90 degrees max is 95.

i can type in chicago search

91 max is 94 and min is 88 and it's

clear right now

or i can type in

las vegas where i actually just was at

and i got very very sick playing a chess

tournament wasn't because of the chess

tournament it's just vegas as a cesspool

of crazy humans doing wild things and so

got a crazy sinus infection but now i'm

recovering so

anyway it was hot it was 120 degrees

there when i was there so there you go

this is the app this is what you're

going to be building right now with the

api knowledge that you've learned so

let's go ahead

and set some ground rules for this and

let me actually also show you

what you actually need to know in order

to be able to build this okay so first

thing we're gonna do is let's open up a

new tab and let's go to replay.com we're

gonna just open up one with html css

javascript okay this one right here and

let's just say

api weather okay and hit create replica

cool so this should just be empty right

now

and then let's go over and open a new

tab

and we're going to go to

rapidapi.com just type in rapidapi.com

now once you're on this website

sign up i am currently logged in okay so

i can log out but like sign up with

either github or google or whatever it's

free just sign up

and then it'll bring you to like

rapidapi.com

all right on here just search for api so

we're going to search for a weather api

so i'm going to just type in weather and

hit enter and you'll see over here that

it shows open weather map this is the

one that we're going to be using this is

the easiest one to use and why we're

using rapid api is because they make

using apis really really really easy

so

let's use them okay they're freaking

awesome so let's click on open weather

map api and i'm going to zoom out just a

little bit so you can see

you can see a little bit better here

let's drag this

back

now you can see our api request is

getting set up i'm going to hover over

this where it says node

axios whatever we're going to switch

that to just javascript fetch because we

want to see how to do

that request in fetch

and this is already kind of showing us

how to retrieve the data from this open

weather api okay

it's putting in a key

it's making a request to the open map

open weather map api and it's trying to

pull some data from there now there's

just a couple of things we're going to

need to do so in order to even use the

free one just we're gonna need to

subscribe to test it doesn't take in a

credit card or anything like that so

just hit subscribe to test

and then choose the one that's a zero

dollars okay this is not gonna ask for a

card it's just free just hit the

subscribe button so we're just going to

hit subscribe

click back on api documentation all

right perfect let's go back to the

javascript fetch mode all right and

just clean up some of these things over

here so for example this over here i'm

going to replace that with chicago so

you're going to notice that it actually

updated that dynamically in the url that

we had remove this all the option

optional ones just remove them double

click and remove double click and remove

double click and remove imperial you can

leave that and then xml double click and

remove so your your url should look

pretty simple fetch url should look

pretty simple right now okay so if i

zoom into this

should basically just say

community open weather map

blah blah blah and then

units imperial okay and the city should

be chicago for now let's see what

happens if i actually try to run this so

let's go up at the top let's hit

test endpoint

run and boom you see that it's actually

already

giving us back a result

okay so let's scroll down here a little

bit

and you can see we have a result here so

we got 13 items back and i'm gonna just

close all of these

items that it sent and it sent us back a

couple of you know it's an object with

like a bunch of different properties

right so we have a cod a name which is

chicago the id of this specific place

what time zone it is in all right

whatever this dt thing is

clouds wind visibility the stuff that

we're going to need

is we're definitely going to need to

pull from weather so we can pull things

like main

it's like clear okay because if we go

back to our app our weather app you can

see that we have this clear here so

we're going to need to pull this and

then after that we just need to pull

these different three different ones so

temp min temp and max temp so if i go

back to rapid api where is min temp max

temp

let's take a look at that so let's see

if we can find the mint max temp all of

that so i'm gonna look inside of main

and here we have temp min temp max and

temp so we have all of the things that

we need so it seems like we get them

back in this object and then the key

that it's in is main okay so for example

if i was to imagine what i will be doing

is i'll get back some something like

data and then from data i'm gonna have

to get access to maybe the first data

point or whatever and then i'm going to

need to get access to main and then

within main so main right here and then

within main i'll probably need to get

access to temp

just like that so that's probably how

i'm going to

get that specific temp that we're

looking for okay so let's go ahead and

try that out let's copy that code

snippet so i'm going to basically copy

this entire thing the other way you can

copy it just hit copy code go over you

don't need to spam it like me being just

an idiot go back here and let's go ahead

and paste that all of that okay so this

is going to be like a bunch of code that

got pasted but

options here is really what you you so

when you're using fetch

you can pass it it can take in a url and

then it can take in options

and then inside of options you can pass

it things like you can pass at things

like

what's your method so this is a get

request and then you can also pass it in

headers and you could pass it in like

the specific key that you need like an

access token because you're gonna need

that

and then who you're sending the request

to all right so that's what options

really is

and if i try to run this let's see if we

actually get back any data

and boom you can actually see on the

bottom right i just get got back all the

data

so dot then console log response now

let's see if

let's see if we can get from that

response right so this is really data

data and let's see if i can do data dot

main

and let's see if that does what we

wanted to do

boom it actually just got us back what

we were looking for after i did data dot

main i didn't even have to do data zero

dot main

and

i'm getting back my temp my temp min and

temp max and those are the things i need

right what was the other thing i need

well i needed that thing where it said

clear

where did it say clear it said clear

under i believe

weather so let's go check again

so when i ran the results i have weather

weather has an array so i have to

probably like

grab the zeroth item from weather so i'm

imagining i gotta do something like this

data

dot weather

of xero

dot

main i imagine i gotta do something like

that

and then that'll get me access to

that'll get me access to what i need

because data will get me access to this

whole thing

whether dot weather will get me access

to

this right here

whether xero will get me access to the

specific

array right there and then dot main

within that will get me access i believe

to this key right here uh this value

right here clear

so let's give that a try and see if that

gets us what we need dot weather of xero

dot what do we say

dot main

clear boom

so you can see exactly how we can

actually get back

uh how we can get access to the things

that we need this is how you can make

that request

so hopefully this sets you kind of in

the right place to get started with this

exercise and i'll show you

now the project that you're going to be

building okay so then you have all the

tools that you need to be able to

complete it so if you go to your

javascript course main

folder right main file right over here

here's where you will find your weather

apps if you actually

go down

you'll see it'll say weather app

right over here

okay

click on that

and this is your weather app that you

can use

and if you go inside of the exercises

for this weather app so let's go to

projects

let's go to weather app let's go to

exercise

and this exercise here

okay we'll walk you through

exactly how you're gonna

do everything inside of this weather app

now you can use this url

here

or you can use the url that

the way that i showed you on rapid api

for bonus points try to just use the

rapid api way

um i think it's easier so then you don't

even have to go to open weather app

weather map

and create your own api but whichever

one is simpler for you do it that way

and here it'll walk you through exactly

how this project

works

okay so it's like hey

you know get the weather data so create

a function that essentially runs and

gets the weather data

um you're gonna need to write something

so if we open up the app on this right

hand side let's go to the weather app

you're gonna need to have the search

input field where you're gonna need to

extract the user

city from and then pop that into your

url and then search it

right so then when they hit search it

pulls all the data this

weather maps api problem is pretty

similar to the superhero app that we

made so i don't think you should have

too much trouble honestly doing this

this is not shouldn't be too challenging

for you

if it is it's all good we'll just walk

through this together and then you have

two functions here okay you have the

search city function all right and then

you have this show weather data

function

and

search city what this is going to do is

based on whatever the user has put in

here it's going to extract the value

that's what search city will do and then

show weather data

will update data on the dom

and

you will have access to

what those variables are as well by

those variables i mean the dom you're

going to need to manipulate the dom so

check out the html on where you actually

need to go and manipulate the

dom

also to make your lives easier i have

put

all the divs you'll need access to all

right so your city name weather type

temp the these are the div

ids okay so these are the actual div ids

if you go into the index.html file

you'll be able to see those specific ids

if you look for them like city name

weather type men temp max temp right and

that's where it goes

those go right there when you change

their inner text so all you'll need to

do is change their inner text

now to get ready for this project what

you need to do is this so for your

file

do the following in your index.html go

back

copy the index.html from

from this exercise file right from the

javascript course copy the entire

index.html file go

and replace it paste it over into the

new replit that you created

do the same thing by going to style.css

and copying this entire thing and going

ahead and pasting this so your styles

should showing be showing up and then

for your script well what you could do

is you could copy pretty much everything

that's here

and then maybe just paste it underneath

for now

okay so that way you have

kind of the piece of code that you and i

worked on together so you have that

already

okay that's just to show you how to pull

data and then the rest is up to you

because this should already show you

enough of what you need to do and really

put you on the right track and then it's

your job to like go okay how do i

retrieve this data and how do i actually

like have this data show up here right

show up

into the right places because this piece

of code

already does that for you so have fun

give this project a try

and

see how much of it you can get done

all right if you get this whole thing

done

huge props if you don't don't stress too

much we'll walk through it together all

right with that said i'll see you

shortly

all right now let's get to work and

let's solve this together let's build

this weather app now we're just gonna do

it from

scratch this is the only piece of code

that we had right and i got that from

rapid api i went to rapid api signed up

for open weather map and then basically

i was able to get my data points and

then it also just makes a code snippet

for you which is really nice just make

sure to choose javascript fetch and then

you can copy and use that exact code

snippet so it makes your life a little

bit easier now i don't even need this

api key right over here because i'm

using

a rapid api one so that makes life even

easier

so

what do we need to do here we need to

get the data based on the city that the

user types well

we're already able to fetch based on the

city right so if i see my fetch request

here i can see that i'm passing in

chicago so i get chicago data if i run

i get clear okay let's remove this

here and i'm just going to leave it to

data let's run this and you can see that

i get back

all of the data

related to

related to chicago right and i can even

see name here so let's just put

data dot

name and let's run it and you can see

chicago well let's say i change this to

marina del rey and let's run this okay i

got some errors right there

marina del rey let's put percent signs

let's see what happens okay no problem

no problem let's go back to open weather

map api and i just want to see

um

when you type in marina del rey how does

it write that in strings

randall right ah percent 20 20 20 just

like that so that's how you represent a

space

in urls as percent 20. so that's marina

percent

20 del rey

cool that's a city

yep so now it's pulling it's searching

at marina del rey and i can also look up

hollywood or whatever i want right and

let's hit run

and it'll pull hollywood and

retrieve its data

so we already know that whatever we want

to put in here it needs to go

right here so this is where like you

know in my mind if i'm looking at this i

will immediately convert this into a

template literal

and right here

okay so const let's just say let city

equals

whatever

city equals whatever

in my mind this is where the user city

is going to go so i'm going to go

user city

because i know that it's something that

the user is going to give me it's not

going to be actually hard coded into my

url so now if i give

let's say hollywood

then when i search it'll say hollywood

right here

if i give detroit or whatever

it will get me detroit yeah

so now

this is this is kind of doing what i

wanted to do we have yet to retrieve the

data what we want to do is obviously

pull the data dynamically from

this user input box when the user types

in the data

right so if we look here we have city

name we have weather type

city name is probably where i imagine

you know we're gonna pull the

the value from that's where the value is

it's in this text box so you want to

pull the value out of there so let's

just say

las vegas

and then we want to pull the value when

the user hits the search button

so we want to make our function

where when the user hits

search

we can extract this

now if we go to our index.html you can

actually see that on the on click method

for this search button we already have

search city

function that gets called so every time

i click this button the search city

function gets called so let's see where

our search city function is it's right

here okay so now let's go ahead

console.log city

and it seems like we're already

pulling the value out of it right here

and we should be able to see the value

so let's type in las vegas let's hit

search

let's hit run i guess let's type in las

vegas and let's hit search and you can

see that we pull las vegas

so by searching city we're already able

to pull the value

now we have this other function which is

called get weather data so i'm just

going to put a const right here

this is really the

you know this piece of code that we

wrote up at the top

okay it's basically that because that's

where we're really making our api

requests i'm just going to first cut my

options and i'm going to pop in my

options right here

because those are like my keys and all

of that stuff and then i'm going to cut

my fetch request

and we can delete this user city because

we don't need that anymore

and boom we can put our fetch request

right get weather data will take in a

city

so now we'll just call this city right

over here because we're already grabbing

that from the

argument right there i don't need this

url right here anymore because we're

using rapid api

cool all right so fetch

fetch will be the city that we're

fetching

and then it will

return that data okay so right now we're

console logging the city names i'm just

going to say console log data

so search city is going to run and then

what we can do is

we can

call our get weather function and pass

the city that we got so let's go ahead

and give it the city okay so let's see

what happens now let's say i hit detroit

and let's hit search

and you can see i just got all this data

on detroit

right and it i can even see that the

name here

says detroit

now let's type in las vegas

boom

name las vegas

and i'm getting all this data back so it

seems like my button is connect my

typing being able to type is connected

when i hit search it's extracting the

data it's sending that over to get

weather data and then that knows how to

make a fetch request

and retrieve the data back

and the last thing really that we need

to do is

really grab that data

and

throw it onto our dom right like

actually show it onto our screen to show

weather data

so this is in this method in this

function right over here show weather

data we just need to update the dom

elements so basically

what i want to do here is

i'm going to take these guys

and update them

okay so for example what do we have temp

right so let's say document

dot get element by id

and temp and we'll set its inner text to

let's just hard code it to 86.6

and then i'm just going to call show

weather data right underneath here

and i'm going to give it

i'm going to just give it some dummy

data right now okay so right now we're

not really going to pass it anything

useful

and let's go las vegas search

boom

and you can see that my temp was 86.6

okay

so

i'm just hard coding this right now but

we're going to need to dynamically pull

the temperature and then pass that

temperature

right actually past the data

and not just

kind of the silly thing we're doing here

so now what i want to do here is

i want to return this data so let's just

do this

so this way i'm returning data

and the next thing i can do is i can

make this function

async

and why i want to do that is i'm about

to run asynchronous code

and i need it to run in the right order

because i want to get the data first and

then i want to show the data but if i

try to run them both at the same time

without doing this what's going to

happen is

this here is going to run first because

this is like synchronous code and then

this here is going to run after because

this is asynchronous that's not what we

want we want this to finish first

and then we want this one to run okay so

i'm going to say async

and we're going to say const

data and i'm going to say await

okay and we can pass this data now to

our show weather data and then we'll

console log the weather data and see if

we're actually getting back anything and

i'll just say

a cookie here so we can see that it's

the actual thing that we're getting

so let's run this

let's type in las vegas hit search

i'm getting back undefined interesting

oh because we're not returning anything

so actually we can put a weight here

and we just got to make sure we return

this fetch

and now

a wait will grab the

[Music]

grab the data and then we'll store that

data and then we'll pass that data so

let's try running this now let's see

what happens

okay las vegas boom now it works and we

get our cookie emoji perfect

so we grab that data

and then we show the weather data okay

so we get weather data and then we show

weather data this is the right way to do

it

and now that we have access to that data

remember how we want to get access to

our temps right so let's go ahead

console log and we're going to say

weather

data dot

i think if you do main

all right let's see what main gets us

let's go las vegas again and main gets

us all the stuff that we need so it gets

us the temp so we could do main dot temp

here

and

i can just copy this and i can paste

that right there let's hit run

and now you can see that we have 106

degrees

temperature automatically being updated

right there now we just need to do min

temp and max temp and

city name needs to go here as well

so we're just going to have a bunch of

document.getelements by ids

now so let's go ahead i'm just going to

paste this line

five times because i have one two

three four five

dom elements that i'm going to need to

update

so one of them is obviously going to be

temp

so let's just say we're good with temp

the next one i'm gonna do is a city name

okay so we're gonna go and see

i think it's literally called city

dash

i could be wrong

city name

yeah i think that should be fine

i think so

we'll see

see if this does what we wanted to do

and let's just do weatherdata.name

so let's try this

let's go ahead las vegas let's hit

search and boom las vegas perfect so

that worked

next one is this right over here how did

we get

clear again let's go check

so we're going to do

dot weather of xero dot main and that'll

get us what we need

okay so we're gonna do dot weather of

xero

[Music]

dot main

and this is going to get us our

this is going to get us

what's the div called div is going to be

called weather type

weather

dash type

and then we have temp

min dash temp and max dash temp so let's

just do both of those min dash temp

max dash temp

okay and then in order to get those i'm

gonna just need to do

temp

underscore

min

temp underscore max i'm just looking at

this right here temp max

and temp

min okay

and now let's give this a try and i

think the entire thing should be working

so let's go las vegas hit search

and we can see las vegas clear

temp men temp maxstamp boom

that was slick

can you believe we just did that right

now like we were speeding through that i

was like what 14 minutes with

explanation we're going fast so let's go

chicago hit search

clear chicago temp mint max temp

right let's type in i don't know that

should probably break oh crap that's

working so i guess you could type in

cities or states

maybe i'll try illinois

beautiful so it works kind of all around

let's check california and just general

nice

so look at that right it's

working really really well it's able to

pull the data fast it's able to show the

data

and if you want to move all of your code

from this into the

javascript exercise page you could do

that as well just make sure you

you know command it copy this and go all

the way back

and then just go into this exercise

one right

and then select it and paste everything

over it

and you should be good to go

right and then your exercise

file should be working so you should be

able to go to your

project exercises you should be able to

click weather app

and then it should be

kind of working in there for you

okay even if right now it's

it might be broken

there you go so now if you go to weather

app right over here it should pull up

and once you put your javascript code

the exercise one should be working

and then the solution one is of course

the final version so that's

you know that's always gonna be

up and running

so there you go that's how you make your

own weather app hopefully that gave you

a clear understanding and everything

makes sense and hopefully you enjoyed it

and i'll see you soon all right i hope

you're having as much fun as i'm having

now let's move on and talk about classes

so how do classes work in javascript

open a new tab let's go to replic.com

all right replit

rep lit.com

open up html css javascript file and

we're going to say a lesson

and we'll talk about

classes

okay

all right

so

how what the heck are classes how do

they work so classes are you know any

time you've seen okay

for example

uh anytime you've done a dot method on

something right that requires you know

about classes

so let's go into our script.js here so

i'll give you examples of where you're

using classes

where you didn't even realize that you

were

all right so

when you say new promise when you say

new promise

you're using classes here okay where

else are you using classes

remember when we can have a

array of nums

and then we could do numstot push

well guess what

you're actually working with the class

you're working with the array class and

that happens to have a method

called.push and we'll talk about

everything too we'll talk about methods

okay we'll talk about properties

properties

we'll talk about

classes

okay

that's the main topic right main topic

is classes and there's all these things

all right so we're going to be building

this ferrari right over here now

let's if you look at this ferrari here

right what do we have

we have and excuse my terrible

photoshopping job but i'm not a

photoshop expert i'm a developer all

right

um

that's what i'm

that's my skill not photoshopping so we

have this ferrari here not fiat because

that car sucks so

here we have our ferrari and it will

have this these these are the properties

that it'll have okay so you'll be able

to do car.name car.model car.wait and

classes are very similar to objects if

you learn objects

you know you you you're kind of in a

you're in a pretty good place like

you're not going to be too confused to

as to what is happening over here now

uh we have this now what are the other

things that we actually need to know

about this right we have all these

properties if you look on the methods

well look at what kind of methods we

have we have car.start we have car.drive

we have car.break and we have car.stop

now those are all the anything with the

dot start and the open close parens like

that those are called methods okay

and those are basically like functions

but anytime you have to do car dot start

then it's just going to be called a

method okay any any function that needs

a dot is a method okay that's another

kind of way to remember it and then

properties are where you're not calling

the function with open close parentheses

so just car.name is ferrari car.model is

whatever 500 car.weight is 850 kg

car.color was supposed to be red and i

photoshopped over it and i made it white

so whatever color is red just imagine

it's a red okay so we're gonna go ahead

and build

this thing and we're going to do it in a

class-based way so we can actually

uh model model this okay and then you'll

be able to create multiple car objects

from it so let's go ahead and do that

now all right so there we go so i'm just

going to leave this over here so you can

see it the entire time okay

all right so

i'm going to go ahead and do class and

we're going to do class car and we're

just going to do this

all right now

we're going to need to create a

constructor and a constructor is really

going to have like the

you know

like

what are the initial type of arguments

and things like that we're going to have

so

you'll also learn about a new keyword

and it'll be called this alright so i'll

show you now so we're going to have

this dot name

okay so the car will take in the name

it will take in let's say a color

and

honestly that's kind of it i don't want

to deal with model and weight yet so

i'll just take in a name

and a color okay for now or maybe it

takes in

[Music]

top speed or something like that

speed

all right

and then we so this this dot name will

be name

this dot color

will be color

and this will make more sense once we

actually call this object okay and

this.speed is going to be whatever speed

you pass in

so now let's create a new object with

this class so i'm going to say

const

car

or ferrari

is

and we're going to say new car

okay so note this new car how we're

doing this new so other things you're

going to see new with is new date

okay so data is a class you're going to

do new promise

promise as a class okay

and we're going to pass in our arguments

here so for name i'm going to say

ferrari

for color we're going to say red and for

speed i don't know i'll say 250 top

speed and i'm just going to console.log

ferrari and let's look in the console

and see what we get

and boom we just got a car object right

there

and it says the name is ferrari the

color is red and the speed is 250

right

beautiful so this is how you will like

create a class and create a constructor

that will like initialize things

instantly now this part this is the

keyword that throws a lot of people off

like what is this

what this refers to guys is

you know how we do

uh

the the name

well

this refers to

ferrari so now when i do so watch this

right so if i do ferrari

dot name and run it

i'll actually get back the name ferrari

okay so let me remove the other console

log just so we can see ferrari now if i

remove this dot name watch what happens

it says undefined

okay

so this here in this case becomes

ferrari ferrari.name

[Music]

and we set its name to the whatever name

was passed in so say it we had passed in

ferrari

so then it becomes ferrari like this so

it goes ferrari.name and sets it to

ferrari okay

so

in other words this argument

gets passed into name

and name is the variable that goes right

here so that's going to be ferrari

and this specific ferrari object that we

just created

that is referred to by this so

everywhere we said this

it's being replaced with the word

ferrari

all right

that's what this does

all right so if i now go this.color and

run this

let's go console.log ferrari dot name

and then we'll do

speed run this and we get ferrari red

250.

okay so you can see we've already

created three properties that this has

okay so these are

these are

properties properties

okay

now we're going to go ahead and create

certain methods for example let's create

a method that's um

you know

car.start or car.drive

okay

um

car dot break so let's say we have

let's say we do car

let's say we do drive

all right and let's just say console log

just drove

two miles

okay

now what we can do is we can go

console.log and i can say ferrari

in this case i don't even need to

console.log it because console.log is

inside of the drive method so we can

actually just say ferrari dot drive

open close parens

and when i run this watch what's gonna

happen

boom it says just drove two miles

okay so that's the drive method

all right let's do car. let's do break

method right

so

how are we going to do break let's say

for break we just want a console log and

we want to say came to a screeching halt

so you try that and see if you could

call dot break

take a few seconds this should take you

only five or seven seconds to do

yourself it's going to be only one line

of code just like on line 18 and then

you should be able to refer to ferrari

dot break so give that a try make sure

you're practicing with me the entire

time so i'll give you five seconds

five

four

three

two

one okay let's go

so i'm going to go ahead here and say

console.log

say

uh coming to a

breaking come breaking

coming to a screeching

halt

or something like that right let's hit

run

and let's do ferrari

dot break

breaking coming to a screeching halt

there you go

okay and uh

what are other methods right so we have

methods like stop so that is probably

like car the car coming to a complete

stop

so

let's say that the car starts off with

like a speed of uh

okay so let's say we have a current

speed as well so we'll go this dot in

everywhere we have speed let's say this

is we we change this with the top speed

okay so i'm going to right click rename

all the occurrences i'm going to say top

speed so maybe this is passing in the

top speed just to make that very clear

now we'll have

this dot current speed

is going to be zero and start all right

so whenever a new car is created well it

isn't driving right now so it'll be zero

but then let's say we

start driving the car

then maybe the speed goes up by 10 mile

uh 10 miles an hour or something

yeah so how we could actually do that is

in our drive method i can just increment

this dot current speed current speed by

10

okay and that just increase the speed by

10

and we'll say console log

and i'll say

driving

driving at

and we'll put

this dot current speed

okay

so let's hit run

and now you can see it says driving

speed at 10 miles an hour so now we have

a new property called desktop current

speed so i can actually go ferrari

dot

current speed

and we can see that

oh no sorry it's not a function so let's

run this again it's not a method

so current speed right now is you can

see undefined

oh i'm sorry the

and if the speed here is undefined

because this is called top speed my

apologies

but if you if you console log dot

current speed you can actually see that

it says it's currently 10 miles an hour

right so let's run this

and you can see it says 10. okay i'm

gonna comment out all the other console

logs so it doesn't get like super

confusing as to what's happening and

i'll console log this just drove two

miles an hour as well

right so it says driving speed at 10

miles an hour

and let's console log before we started

driving the car as well

so in the start you can see the speed is

zero

right here

right if you look

we see that the speed is zero right

there

right then after we drive

you can see that the speed is 10 miles

an hour

well what if we

do the drive method again what will our

speed be can you guess

take five seconds and try to guess this

five four three two one

okay let's see if you guessed it right

beautiful okay nice if you guessed 20

because it increments it by 10 and if

you do drive multiple if i do drive two

more times what is current speed going

to be at this point take a guess i'll

give you five seconds five four three

two one

and it's gonna be 40 miles an hour okay

driving speed at 30 miles an hour

driving speed at 40 miles an hour

so the car is getting like faster and

faster

now what we could do is we could kind of

get fancy and we could do a set timeout

where basically if we drive for one

second

uh it gets up to a certain certain speed

if we drive for two seconds maybe it

gets up to like

35 miles an hour or something and then

when we get to 2.8 or 2.9 seconds

maybe it's it does 60 miles an hour

right so what is that actually um

ferrari

let's see 0 to 60

how long does it do it in about 3 point

how fast is a ferrari

so let's see their seconds right so

three seconds 2.9 seconds 2.5 seconds

what's crazy is that rivian which is one

of these trucks that is like my absolute

favorite right now

dad that is like faster than a ferrari

and it's a truck and it does it in three

seconds

so some ferraris we have go

and do it in 2.9 seconds whatever we'll

just do 2.9 seconds right

so

what we can do is we can even like get

fancy with it and we can create a method

that like takes us to 60 seconds 60

miles an hour

right so let's call it zero

260.

and what this does is maybe it runs a

set timeout

and then it console logs

that was fast

or something right

and let's make let's put some squigglies

around this actually

because we want this to be like a

function

and we want to write probably more

things in it

and then we want to set the current

speed

to 60

because i'm going to set the current

speed to 60.

so let's see if this works kind of as

expected so we're going to do console

log

we don't need to console.log we can

actually just do ferrari

dot

0 to 60

and run this

and

let's see

that was fast okay and now if we check

so like if i comment out all these other

lines

and uh let's comment out this line as

well

and this one

and now let's just check the speed so

i'm just gonna get this console log one

and put it right here and run it that

was fast so because it's asynchronous

notice what happened

it ran and told me what its speed was

actually before that code finished

running so we what we want to do

is we could turn this actually into a

promise if we wanted to get kind of

advanced with it and then get this

promise and then once it resolves we

could do something with it if we want so

we could do

return new

promise

and then we can like

resolve

resolve comma reject

and kind of get fancy with it

but we can try doing a simpler way first

because

simpler ways are usually you know we

like them

and we can actually just

grab the current speed like this okay so

we can grab the current speed from here

after it changes it to 60. so let's try

running it now

and you can see that the current speed

uh at this point has been

you know turned into 60.

so if we do it like this

it'll work and it'll it'll do what we

expect it to do

now for break what we want to do is see

if you can make it where break brings

the speed

down by 10. okay so if drive brings the

speed up by 10 see if you can make it

where

brake brings the speed down by 10 okay

so give it a try pause the video i'll

give you five seconds to pause the video

and try it on your own i think you'll be

able to do it yourself okay so

let's do a countdown five

four three two

one

okay let's give it a try now

so let's do it together if you hadn't

already and if you did great job okay

and if you didn't it's okay we'll figure

it out together

so for break what i want to do is i

basically want to say

hey um i can remove this console log for

now don't care about it and i will

simply say set the current speed

to

um

minus equals

10.

okay so this will just decrement the

speed by 10.

and we'll

we'll put a console log here and we'll

say

breaking

so

let's comment out all of these lines

here

okay

and let's comment down this one and i'll

just go right here

so we got the ferrari

right we have the ferrari now what do we

want to do i do ferrari dot drive so

this should bring it up by 10 miles an

hour and let's print out the speed so

i'll console log

speed

or sorry ferrari

dot current speed

so let's run this and the current speed

is 10 miles an hour

okay now let's do ferrari dot break

and then we'll console log

the speed

and you can see that when i did drive

it increased it by 10 miles an hour and

then breaking it

decreased it by 10 and so now we're at

zero miles an hour okay

now what if we wanted to make stop where

stop essentially just brings the speed

down to zero regardless of where you're

at so to emphasize that first let's do

drive multiple times here

and see if before i continue the video

if you can guess what the speed is going

to be

on line 46 so i'll give you five seconds

to figure that out

5

four

three

two

one

all right so how i'm going to figure

this out is one two three four five five

multiplied by 10 is 50 so this should

get you to 50 miles an hour they should

decrement by 10

this should get us 40 miles an hour

let's run this and we get our speed at

40 miles an hour okay

so now what we want to do is we want to

implement the

stop method okay so try to implement it

yourself i'll give you some time to do

it you should be able to do it okay and

if you're not going to pause the video

or if you have paused the video and

you're back

let's figure it out together now so i'm

just going to say

now i guess it would make more sense to

say coming

to a screeching

halt

right and then we can actually say this

dot current speed and we can actually

set it to just equal to zero okay so

like basically we're going to reset it

to zero

so let's try

ferrari dot

stop

and now can you guess what line 52 is

gonna say

okay take a guess there and let's run

and boom you can see that now we're at

zero miles an hour all right so we were

driving at 10 driving 20 driving speed

30 40 50

50 and then we were breaking and then we

came to a screeching halt and now we're

at zero miles an hour and the car has

effectively

come to a full stop

all right now let's grab a different car

let's get a porsche right right here and

let's see if you can create

uh a new object with a porsche so give

that a try and let's say its speed is

250 miles an hour as well okay or 240

miles an hour

so you have a porsche

[Music]

porsche

okay

color is yellow right and then speed of

this is let's say 250 miles an hour so

make a new object with this and then see

if you could do things like drive it or

get its current speed and things of that

nature give that a try

give that a try

okay

and while you give that a try

one thing we can do is um let's go down

here okay give that a try pause the

video and see if you can actually try

this on your own so you take five

seconds five four

three two one

okay

now

here's how you do it okay let's do it

together so

i'm going to make

porsche

right

and it's gonna be a new car and i'm

gonna say

porsche

and color is yellow

and top speed is let's say 250 miles an

hour

okay

and uh let's go ahead and do porsche

dot name

and we'll console log it

and we'll do dot color

and we'll do

top speed

and let's run this and see if we

actually get it yep we get porsche

it's yellow and the top speed is 250.

can we drive it let's try it

porsche.drive

and let's do let's drive it like

multiple times

all right

and you can see boom the top speed uh

now we're at 50 miles an hour if you

want you could also turn it into a loop

right so we could basically say

you could run it for

five times

or more if you want so let's say we have

an array of one two three four five

and i can say for each

and i can say

i don't care about the value

i don't need to use it and i can simply

say

porsche

[Music]

dot drive

so all this function is doing is i don't

care about these

and i'm just saying hey increment

porsche.draw uh just do porsha.drive

essentially five times so this gives me

a loop that lets me run this piece of

code five times let's try it

okay

i cannot read properties of undefined on

line five

interesting

line five

what's happening on line five

okay let's comment this out i guess

let's try it

okay so actually let's do this because

nums is also of class type array

or sorry array arrays are

class type array so you have to

instantiate them first and then you can

actually do a dot for each so now i can

do nums.4 each

and now it will actually work okay so

now i can actually try

run

and you can see that we just looped

through five times and

you know really floored it and gave you

know ran our porsche

now let's see if we can do

0 to 60 for our porsche so porsche.0260

and let's run this and let's see if that

runs

okay and it goes phew that was fast now

for our timeout we want to make sure

that we give it like a couple of seconds

right so we want to say 3000

so this will wait for

three seconds and then it'll say that

was fast

and then print out the current speed of

the car etc so let's try it now

and

boom that happened three seconds later

it goes phew that was fast

okay so we have zero to 60 on this as

well

and then can we do porsche dot stop

and then check porsche

dot current

speed

and we'll console

log this and run this now

and then boom we have speed is zero

okay there you go

oftentimes you'll see these get and set

methods a lot so i'll show you an

example of that and you can try to make

this

yourself as well so i'll do

get

current speed you can already kind of

see what this method is going to do okay

and

see if you could write this yourself

it's going to be very very very very

easy okay it's just going to do one line

here

um literally take like four to five

seconds try to write it on your own as

well

and five four three two one okay

so get current speed and you can just

say return current speed okay there

isn't a huge amazing use case for this

here but i'm just showing you this

because a lot of classes will have these

getters what they call

getters setters

so i i want you to get used to this so

they'll have ton of like get methods and

then they'll have ton of set methods

that like set the current speed

right so basically this drive method is

really like set the speed or like update

the speed back by a certain thing

um

we could even give it like uh we could

even give it a method like target speed

where you as a user can actually pass in

the speech actually let's do that

because you've seen how to call methods

but you haven't seen how to pass

arguments to methods so how about

you could actually call the method drive

and put in a

like a number here like a speed number

and instead of incremented incrementing

this by plus 10

it'll increment it by the speed that you

give it

okay so now when we call that drive now

drive needs something okay and uh i can

also show you default arguments in

javascript which are really nice so if

you don't pass in an argument it'll just

give you 10. for example if i try to run

now my code is going to kind of like

not work

you see how we have these nands

everywhere like nan

because

we're not passing in a speed

when we call our

drive method so if you see our drive

method here we're not passing in a speed

here right

so if we actually just give it a

equals 10 that's a default argument so

if i don't pass in a speed it'll set

that to just be 10. so let's give it a

try now and see if that works

yes it does right

but let's go ahead and give some speed

so for example for the porsche what i'll

do is

i will comment out this line where i

gave it a

like a

drove it five times here

what i'll do instead

and i'll comment out this nums line too

what i'll do instead is i'll say porsche

dot

drive and let's say i say 40

okay

and then we console log and we get the

current speed so let's go ahead and

console log here and run this

and you can see that it instantly just

went it shot up to 40.

right it instantly shot up to 40 here

let's

do

80.

okay let's do 40 here

and let's do

maybe another 80.

now what's gonna happen so i did 40 here

for drive and i did 80 here for drive

what do you think line 69 is going to

get us

what's the speed going to be 5 4 3 2 1.

speed's going to be 40 plus 80 right

it's all incrementing on top of each

other so it's going to be

120 let's run it

and boom

we got 120

okay so

there you go this is how you make

basics of classes and this is an example

with cars if you have cars how can you

make different classes and give cars

different methods and hopefully this was

like a really visual example so it kind

of

got certain concepts through for you so

that's what's happening with classes

okay so to give you some other real

world example of this

and you know i want i do want to talk

about nums and stuff like that and i'll

kind of foreshadow it a little bit

but here's a real world example

so let's say we have const numbers

and we have this array right here

and we do numbers dot push and i say 4

and i do console log numbers

what is numbers going to say

is numbers going to give me back an

array 1 2 3

or is it going to give me back an array

of one two three four which one is it

gonna be

if you guess that it's gonna give me

back an array with one two three four

good job that's exactly right

why is that happening

because we're doing this dot push so

what is dot push is dot push let me ask

you is dot push a property

is dot push

a function or is dot push a method

uh or is it something else

what's not push

if you guess that dot push is a method

or a property that's not right because

property is if i didn't have any

function call here okay so that would be

a property it's not a property

if you said function that would not be

right because

a function is if you had to call push

like this because you have to do dot

push it's not a function

if you said method

you are completely correct good job okay

so this is an example of a method

method so if it's a method well then

that means whenever methods are involved

there must be classes

because you can only have methods inside

of classes i'll write it as a note you

can only have methods

inside of classes

so you must have a class here well that

basically means that numbers which is of

type array

that that means that that's a class

okay it's its own class and that class

has methods like dot push

and there has there's something i

haven't shown you yet but it's called

type of so if i actually have an array

so let me clear this console and let me

zoom in here so you can see better so if

i do type of and i say

one two three array

okay

here it's giving me okay what's the type

of this and it says object right if i do

type of

and let's say i do

two it says type of number if i say

hello

right it tells me string

so this is a type of either object but

specifically this is of array class okay

so sometimes javascript is weird it ends

up calling a lot of things objects but

this is really like an array class

and classes are objects sometimes that's

okay

then you have number then you have

string so that's why like when you have

a string it has its own methods like dot

split

right where it turns that string into an

array

um or you could have an array with one

two three

and you could say dot join

join this with strawberries

right and then when i do this it joins

one two three with strawberries

so

there are classes which have their own

method so if you were to visualize this

so for example when i have arrays right

here

like arrays right what is array so

imagine it like this array is of class

uh or it's a class array and then you

might have different methods like you

might have a join method

and you might have the

push method

right

and then we can actually even try

implementing our own push okay and we we

could create our own push and see if

that works exactly like push does and so

let's give that a try but first let's

just see how

certain array methods work okay so for

example i'm gonna do

so i have one two three

this is an array right if i do dot push

and i say four you can see that i've

added a four to that array right so

let's just go to one two three again

perfect okay so we have this one two

three array now

one thing you could do

to an array is i could actually get the

zeroth property of an array and i can

change it

sorry about that

um i have a chess tournament coming up

so my friend is calling me for that it's

tomorrow in las vegas

and it's like a hundred and four degrees

severe heat warnings there but i'm

excited and i'm gonna go play it there

it's the national open chess tournament

and they have a hundred thousand dollar

prize guaranteed

i'm not looking to win i'm just looking

to have a good time it's going to be fun

playing on the u 2100 if any of you guys

are chess nerds

let's get back to this

so let's say i have this or so let's say

i crit let me create an array

so x equals we'll say 1 2 3. okay so i

have this array right here 1 2 3.

now i can actually

change some of the properties

in here so i could actually do

x of 0

and i can change that to

i don't know 10.

and now when you look at x notice that

i've changed at that 0th position and

now you have a 10. okay well what if i

change at position 2 and i do x of 2

is now

whatever x of 2 was plus 7. what do you

think is going to happen

what do you think is going to happen

here

so x of 2 will get you access to the

the third index right so this or the

second index zero index right this is a

zero this is a one and this is a two

and i'm setting x of 2 to whatever x of

2 was plus 7. what do you think is going

to happen there well this 3 is going to

actually turn into a plus 7. so let's

try it

right and let's run x and you can see

that now i have 10 here and 10 there so

you could mutate an array right

now

by doing this what if we access an

a location that we haven't we don't even

see there so let's give that a try so

let's see if i can do

x of 3

right which doesn't exist

and say i say

uh apple

and now we do x and you can actually see

i have 10 to 10 apple

so i could actually add things to an

array

by getting like the last index of the

array and adding things there

whoa

that's pretty bizarre huh

so using this knowledge we can actually

implement our own

push method

okay and i'll show you how you can

actually add methods to

the array data type so javascript allows

you to do array.prototype and this

allows you to just get access to the

array like class

and we can actually now create our own

method here and say

my push okay so this is going to be our

push method that we're creating

and we're going to say it's going to be

a function

okay and what this function is going to

do

is let's for now let's just say it's

going to get this dot length okay this

this will refer to the array you're

calling the dot whatever on so let's

create const fruits

and i'm going to say

banana

let's say

blackberry that's not blackberry

uh berry is fine oh we don't have to

apparently what happened to it

strawberry

and then we'll have a cookie okay so

apparently cookie's a fruit but

hey let's just go with it

and now let's do

console.log and i'm going to say

fruits.mypush

and call it as a method okay fruit's not

my push let's call it the method let's

hit run and let's see what happens here

okay we're getting an error somewhere

let's see where we're getting that error

it says line 97.

oh because i'm not like calling typeof

on anything so let's just comment that

out

let's run this now

and you can see i have one two three

four

okay

and right now it says undefined because

i'm not having it return anything so

let's say return dot length

so it should return length of three and

we're we're getting that three we were

looking for

okay

uh let's get our cars to

get our cars to kind of calm down a bit

so i'll just comment all of that out

all right

so and then let's comment out our array

stuff here as well

so we should just have fruits now if i

add an additional fruit in here

let's say i add a pear

or an apple what do you think the length

is going to say do you think it's going

to say 3 do you think it's going to say

5 you think it's going to say 10 what do

you think is going to say

let's try running it boom 5 because i

have 5 items in here

so in order to do the thing right if i

have an array with five items then all i

have to do

is say something along the lines of

my array

five

and in the fifth position

i can put in

whatever item i pass so my item

okay

so in this function

we'll pass in item

okay

and then we can actually just pull the

item from here

and let's actually just see first if we

can actually get access to

our item through that right so let's

just say return item

and i'll pass in cookie

the word cookie and let's run this

and you can see

that my push function like meth run my

my push method runs

it calls this

and i can actually call it on type array

right i'm creating my own methods for

the array

and then it's actually returning the

cookie right here

right so in order to do this now i have

all the pieces of the puzzle i can do

grab this array okay so this will get

you the actual array that you're passing

it so let's run this just so you can see

and you can see this refers to the

actual array that was passed in okay so

hopefully that demystifies the word this

a lot for you okay because that's what

this is referring to

and now we're gonna say

it's whatever you're calling this dot

thing on is usually like this okay so

it's referring to like fruits in this

case now if i do another dot

that dot will be referring to whatever

this

would be

okay

so now i'm gonna say

this it's i know it's an array

and

i know what i want to do

is

i want to return the array

okay

and

on its fifth element around his fifth

position zero because

let's just go through this this is zero

this is one this is two this is three

this is four so in its fifth position

right over here i wanna add in a

um

a

what other fruit is left that i haven't

covered yet

a kiwi do we have a kiwi in here

apparently we do nice

so

on that position i want to set that to a

kiwi

okay

and then we return this so let's go

ahead and try that

and you can see boom we actually now

have a kiwi

right over here okay

so

that's super cool but this five is hard

coded how could we get this five in a

dynamic way

well if we have access to this can we do

this dot length and get access

and then we're just going to set that to

a kiwi but in instead of a kiwi

we can just set it to an item whatever

item we pass it so now we can pass the

kiwi from here

and let's run this

and you can see that we pass in the kiwi

went here

and it plugged it in

boom

and so now we have our own push method

right we can actually just use our own

push to push whatever we want so let's

try pushing a couple of things and let's

then print out our our array okay so

ignore that

so let's go ahead and and push a bunch

of stuff so i'm going to push

more cookies

i'm gonna push

more strawberries

okay i'm gonna push

another

i'm gonna push an orange

okay

and then we're gonna console

fruits and let's see what happens

and there you go all of the things that

we actually pushed

right got added

all of these guys that we pushed here

four new fruits

you can see that we now have those four

new

fruits

right added in

right there

okay

so you can extend

classes you can extend

uh array data types like this you could

extend other data types like this so you

could extend

so many things and then you know now

hopefully other things to you

might make sense too for example

if you have an object right so let's say

i create an object called things

equal or let's say i create an object

called actor

and

name

is uh

jamie

foxx

and age is i don't know how old he is 37

right

and um

money is

i don't know whatever something random

right so now i have an actor how do i

get the keys of this actor i got to use

a method on the actor

you know object so object is also like

its own class and it has its own method

so if you were to imagine it you should

imagine it like this i have a class

object and it has different methods for

example it has a method called

keys all right so now watch what happens

when i do

object

dot keys and i pass it actor

okay

so i can actually pass it actor and boom

i get name age money

all right well actually object keys is a

little bit different it's it is on the

object class so you could do object.keys

and pass past the actors so that's

fair enough that's still like that's

still a method dot keys okay so

there are a lot of things that are um

all right and you can also do this you

can also do dot values

and get all the values back

right so you could do dot keys get the

get the keys you could do dot values

it'll give you all the values of that

object

so

there are so many use cases of this

knowledge and this information and if

you deep dive into it now it'll save you

so much pain

in the future because it gets so much

harder

if you have like

shaky foundations and shaky basics and

then you try to go and build you know

learn more complex stuff on top of it

you're just gonna have so much trouble

but if you learn this now and you can

extend these classes and add your

methods and do a whole bunch of stuff

like this

you're gonna be

just such a badass developer in the

future and you're gonna be so much

stronger than most people and where

other people get stuck you're gonna be

flying past

so i hope this made sense

i do i would like to do some more kind

of exercises with classes because

i think you should get very used to

seeing them like everything under the

hood is going to be some type of class

some type of object everything under the

hood is going to be

methods and all that type of stuff going

on so if you start getting used to

seeing all of this now i think it's

going to be good for you so we're going

to do a few more examples together

so all of these notes here i'm going to

leave them for you

so you have access to them kind of

whenever you want

okay let's go let's make sure that

they're running

and if you ever want to run them you can

just copy them into a new rupple and run

it okay and all of these notes i'm going

to take them we're going to go back to

our javascript course

and then inside of classes i'm going to

create a new

folder

okay and in this folder

i'm just gonna call it or actually this

could work really well as a

yeah so that's good actually so let's go

inside of here we're gonna create a new

folder and i'm gonna call it

car

class okay

and then inside of here we're going to

make a new file we're just going to say

how did we name them we should just call

them script.js everywhere for fighting

game would it be yeah we just call

script.js that's fine

and then all of this is gonna be in here

for you okay so you're gonna be able to

see

how do you actually work with uh

you know how did we create the car class

and that lesson is gonna be there so you

can just go and take a look at it at any

given time that you want all right to

finish this off i'm gonna leave you with

an exercise

try creating a new replit a new rupple

okay on replit

with just html css javascript and try

creating a bank class

okay so create a bank class

and then it should have methods such as

withdraw

and it should have methods such as

deposit okay

and it should have properties

such as

balance okay

so for example i should be able to do

[Music]

um

you know kazi accounts

and i should be able to do new bank

account or whatever

account

um and you could call the class bank

account or bank i don't care whatever

and then maybe you could uh start it off

with the initial balance okay so and

then if you ever do self dot or

sorry python world desktop balance it

should get me the current balance in

this case it should get me back you know

100.

if i do

this dot

deposits 100

the balance should get incremented so

what should happen is give me one second

and i'll show you what should happen

okay let's move this up here

boom

[Music]

all right if i do that then

after this if i actually take a look at

this dot balance

that should become 200.

if i do this dot withdraw

100

then when i look at this.balance

that should become 100 okay because i

just subtracted it

so

i want you to give this a shot

see how far

you can take it and how much of it you

can complete i really believe you should

be able to do this entire thing

and you should be able to call these

methods

okay and then

do them right so it should be this that

deposit yep 100 like this it's a

method right and then it takes in a

function sorry it's a method and it has

a parameter that you have to pass it so

in this case i'm going to pass it 100

and then increments it by 100 if i do

5000 or 10 000 it should increment by

that amount

on the other edge cases

let me ask you this if you have zero

dollars in the bank should you be able

to withdraw a hundred dollars so let's

say that this dot balance

or let's say you try to withdraw in this

case

two hundred dollars when you only have a

hundred dollars left should you be able

to do that

no you should not

so

it should catch that

it should stop that from happening

and

it should print out an error message

telling the user hey you cannot withdraw

more than what you don't have

in order and if you want to make it

really jacked and really amazing try

adding a ui to this project i don't care

if it's ugly it doesn't matter

but see if you can add a ui to this as

well so it has like buttons i could

press for withdraw i could click them

and they can help me withdraw

and then i click a button it helps me

deposits deposit

so maybe

so let's actually draw this out right so

i have a

button here

for withdraw

draw

i have another button

okay

i have another button

right here or wherever it doesn't matter

for

deposit i don't care about the ui as

long as you get get it done

and then we have another

button here

or not a button but like rather maybe

you have a

you know maybe here it actually says

what the balance is so it just says like

hit a balance right now

is 100 or whatever so it actually

literally has the balance written out

and then the balance increases and you

can see it on the screen

right so you hit withdraw you hit

deposit it either decrements or

increments

and you know and then if there are any

other methods or anything like that you

could think about adding them uh maybe

there is like you want to close your

checking account or something like that

and then just clears up everything

you know

but

this is like the main crux of it so

try doing this see if you can

nail this one you should definitely able

to nail this exercise

and then once you give it a full solid

attempt

then we'll work together and code

together and

make the finished version

got it all right i hope you're excited

go give it a try and then come back and

we'll do this together all right now

let's work and create that bank class

that we were talking about

so let's go ahead and do this so i have

this bang class the first thing that

comes to my mind before i even start

thinking about anything is bank class

bank just like this

okay

um and

you know i'm like okay cool that's

that's that's a good start

what's next

well what's next is i have certain

methods i have a draw method so i'm just

going to go ahead and kind of create

that

and then i have a deposit method so i'm

going to go ahead and create that

okay

the

the balance is going to be something

that's going to be instantiated so it's

going to be like right when the class is

created the balance is going to be

created right at the exact same time so

for that i'm going to need constructor

and the construction is going to just be

kind of empty like this and i'm going to

say

i'm going to grab balance and we're

going to say this stop balance is

whatever the balance was passed in then

all withdrawal does in my mind is

withdraw

right this this function right over here

withdraw

what this does is it should just take

this dot balance and increment it by

whatever amount the user wants

and we should have pretty much the same

thing here for deposit but we decrement

it oh sorry the other way the other way

the other way decrement on withdrawal

and increment on deposit right because

we're depositing money and we're taking

out money

so so far looks pretty good to me looks

like we're almost done honestly with

this let's go ahead and

do const causey

checking and we'll say cla new bank

and uh we're going to put in we're going

to start it off with a deposit of 100

okay let's go ahead and console

log

causey checking

dot balance

okay

and then we're simply going to i'm gonna

just move it a little bit out of the way

here and we're gonna say run

okay and you can see that i'm getting

back uh 100 here which is great

you know that's exactly what i had

expected when we made this

now let's try adding so i'm going to say

causeychecking.deposit

and we're going to add in 100 and then

let's print out the balance again

okay and now the balance is 200

and what we can do is inside of our

withdraw function i can just add an or

end deposit i can add a console log

right here

and i can say

so it just shows us the balance right

away okay so

[Music]

that won't work so i'll just do balance

call in this dot balance like that okay

and you could call this whatever you

want that doesn't matter and this in

objects is the same thing as if you did

balance

okay

so both are the same so i'm just going

to copy this

and i'll also paste it over here

so we have

um

so basically as soon as it updates the

balance amount it should just show it

okay so then that way we don't have to

do all these

a ton of console logs

okay

and maybe let's add another console log

that says

console.log

deposited

and the amount

okay

and then we'll do the same thing for

withdraw and we'll say with

drew

the amount so let's run it

and now you can see it says deposit it

100 right

and we can put in

so i just put a dollar sign here

and then we can put amount like that so

it'll show it with the dollar sign so

it's a deposit 100 so balance is now

200.

okay

and we can we can do this same trick

that we did here for with

for withdrawing okay

so

let's try with draw

so after withdrawing balance is 100

let's withdraw one more time balance is

100 0 right now here's going to be the

problem

if i try to withdraw one more time do

you think it's gonna let me withdraw

i'll give you five seconds to figure

that out five four three two one

yes it's gonna let me withdraw right

watch what happens boom negative 100

should i be able to withdraw allowed to

withdraw money that i don't have the

answer is resounding

no right heck no i should not be allowed

to do that that is crazy otherwise

would be super rich right all of us

would be insanely rich so what we want

to do in that case is

add a guard clause inside of our

withdrawal

okay so we're going to say guard clause

so protect against this and i'm just

going to say if and hopefully you tried

this and you got it if you did good job

and if you didn't that's okay but like

if you didn't get it and you want to

attempt it now try pausing it now

and basically what i'm gonna say is i'm

gonna say

if

this dot balance is less than

or equal

to zero then just return like meaning

don't don't run

don't run this function method just stop

it right here okay so let's try running

let's try this again and let's see what

happens

okay and maybe we can even say this and

and say um

you know or maybe we can we can like

throw an error here too or a console log

and just say

can't

not

withdraw

you cannot withdraw

more than

what you have so if we're already at

zero this will stop us this statement

will stop us with drawing if we're

already at zero okay so for example if i

try running this now

it says you cannot withdraw more than

what you have so this is really good for

zero but the the problem still remains

for example if my balance was at 100 i

could still withdraw 200 right that

won't we won't be stopped by that let's

say

i try 200 and run this you can see now

my balance is negative 100 right and

then it stops me after that

but that's not what should happen we

should be able to withdraw before that

so maybe what we want to check is we

want to say if this dot balance minus

the amount

that we're being passed in

if that's less than or equal to zero

then just stop so let's try running it

now and you'll see that it doesn't let

us withdraw less than you know once

we're at 100 it doesn't let us withdraw

and it stops us twice and stops us both

times so we'll not be able to withdraw

any more than we have right so for

example if i try to withdraw let's say a

thousand dollars it'll just say sorry

can now withdraw it all right and the

our balance will still be at at 200 okay

so maybe we can i can do this it's like

i can print out the balance as well here

right so you can now withdraw more than

what you have and then boom shows the

balance right there so that stops it and

now you can you can try

depositing you know as much as you want

you can deposit ten thousand ten

thousand ten thousand if you look at

your balance it'll be twenty nine

thousand one hundred now let's say you

start with drawing twenty thousand and

then you try with drawing 5 000 and then

another 5 000. let's see what happens so

a bunch of your deposits deposited 1000

withdrew

so deposited one 10 000 deposited 10 000

and then you tried to withdraw so it's

like withdrew 1000 withdrew 20 000 so

balance is not 90 100 from 29 000 that

makes sense

but when your balance got to 4 100 right

and you try to withdraw 5 000 well you

ca it says you can't you can't withdraw

five thousand dollars so

that's how those methods are working so

that's really really good now the only

thing that was left is if you could kind

of create a ui for this right so let's

go ahead and try to create a ui for this

that shouldn't be that hard so the first

things i want to do in order to create a

ui is

i need some buttons

all right i'll create another button

here

and for this button we'll call it

we'll give this button an id of deposit

deposits we'll give this button id of

give this button an id of withdrawal

okay so we got two buttons here

and it'll say deposit this button will

say

withdraw so a little plus sign to show

that that adds money this withdraws

minus sign that that withdraws money

we'll remove this hello world from there

okay so now we have deposit and withdraw

um we'll have the text for

your balance right there so

i will have a div here

and then inside of this div i will have

a p tag

and this p tag will say

uh

balance

right and then balance will be zero for

now and then we'll give this an id

of balance this div because then we're

going to be able to change its inner

attacks or it's inner html

right

perfect so we got balance right there

cool

so

we have our balance we have deposit

withdraw

and now what we want to do is when we

click

we want certain functions to run so what

i can do and there's this nice little

trick since i have this deposit id right

here i could actually just

say i believe deposit and should run

this i think so

but

let's uh let's not be that hacky let's

try to avoid being that that degenerate

so i'm just gonna say const

deposit button and we're gonna

[Music]

documents

dot get elements by id and we're gonna

say deposit

okay

and then i'm gonna do the same thing

and we'll get the

withdrawal

button and all we're going to do is

we're just going to attach listeners to

this i'm going to say deposit button dot

on click and every time you do on click

we're going to do you know quasi

checking and this we'll just do cause

you checking that withdraw that's fine

cause you checking that

withdraw

and um oh okay that's a good that's a

good point we'll also have to do a input

field for like how much do we want to

deposit or withdraw right so let's do

input and we'll give this an id of

amount so let's go back and i will

simply

go

amount input and then we will say amount

so if i hit run again you'll see i have

a field above here because that will

basically tell us how much do we want to

uh withdraw or deposit so i'm going to

say withdraw

whatever the amount input dot value is

okay

and let's see if that actually

does anything right so i'm gonna

i'm just gonna console.log

and i will say amount

input dot value

[Music]

and let's see if that does what we

wanted to do so i'll say 23 and i'll run

this

sorry 23 and then i'll hit

i actually got to attach it to something

right so for now i'll remove this line

and i'll just say

amount input dot value and just console

log it for me please

let's run this and let's hit deposit

deposit deposit 23 deposit 25 deposit

deposit that does not do what we want it

to do let's just console log anything

for now just to see if things are

attached the right way

let's run this let's deposit deposit

deposit did it this is still not doing

what we wanted to do okay so let's go

back to our deposit button it has the

correct id

of

deposit right

so the id is correct let's go back

pause it this is going to be withdrawal

and so i'm saying deposit button

dot on click that let's try that

ah interesting

okay let's open this up let's just see

if it's not a bug

hit inspect

console and let's hit draw

it is not a bug interesting okay we're

doing something wrong we'll figure it

out

oh yes i forgot on click takes in a

uh anonymous function right so let's do

this

and now let's hit deposit yes so it runs

every single time so now the button

click is being detected correctly that's

good

now let's do amount input dot value

and let's run that

oops let's run this

let's do 23 deposit 25 4 deposit 25

deposit now this part is running

correctly as well so if i do 26

deposit

right works

works correctly good okay let's move it

to a new

line so things don't get that squished

okay so i have attached a listener on

this on click

now let's try doing that withdraw thing

that we were doing with

draw

[Music]

right kazi checking out withdraw amount

dot input value okay

and

let's try doing that so i'll do ten

dollars uh oh sorry not withdraw right

deposit

because this is a deposit button so

let's run the code again let's hit ten

dollars deposit boom the deposit just

went up by ten but it's attaching the

string so now it doesn't say 4

100 now it says like 410 000

so what we want to do is we want this to

be a number and yes okay so we want we

want that to be a number and what we

could do is we could just call dot value

on here and we could just call number on

this so now and then amount we don't

need it to be an input because it's

actually an amount now and we just pass

this amount around now so now i could

set deposit amount

okay so if i said 10 here hit deposit

amount input is not defined

so this is just the amount

and i don't even need that line anymore

let's run it again

let's do ten dollars deposit

okay let's do twenty dollars deposit

oh

interesting we actually can't do it like

that so let's go back

let's keep that amount input there

once we get this query selector then we

have to do dot value because if we just

do dot value it's going to just get the

value that it initially had when the

script loaded and that's it and then

every time you click it it's just going

to get you back that value but if you

keep it like this dom element

and then at the time of the click pull

the value then you're actually going to

get the correct value

so i apologize but you're going to have

to keep doing that value here and then

you're going to have to

type cast that to a number

like this okay so this you'll kind of

have to do

each time okay so let's run this

and

see this i don't need this here anymore

let's run it again

all right i'm going to deposit ten

dollars and now you can see that the ten

dollars are deposited correctly

okay

let's try depositing a thousand dollars

let's try depositing 20 000

right

and you can see

at the bottom right there

now it's doing it correctly right we're

depositing the correct amount

now

let's try doing the same thing for the

withdrawal button so if you haven't done

it yet try doing the withdrawal button

yourself and see if you can get it i'll

give you five seconds five

four three two

one

all right let's try the withdrawal

button together so i'm gonna paste this

i'm gonna replace this with withdraw

and then

we're gonna use the withdraw method here

okay and we're just gonna do number

amount input.value same way

let's

run this and i'm gonna say

100 deposit so balance is 42

and now withdraw balance 4 100. so now

deposit and withdraw are working all i

need to do is update the dom after

we do this deposit right

so as soon as that happens we're going

to update the dom

and how what i'm going to do is i have

the

amount

not the amount input i need the

i need the balance right so i need this

balance div

so let's go back and we're going to do

const balance

div

document.getelementbyd

and we're going to say balance

okay so it's going to get us to div

and i'm going to say

inner text

and we're going to set that to and it's

going to say balanced

um

and we're going to pass in

this right

there okay

you could also just do this so we can

create a new variable

use that here

and use that here okay and then do the

same thing for the withdrawal function

and then just replace it with amount so

then it's cleaner

okay

so there we go quasi checking that

deposit amount

and then the balance is going to read

that amount and then we're going to do

the same thing right here balance div

enter texas amount let's run this let's

hit 10

boom balance is 10. let's do

30.

now you can see balance is 30. right but

the problem here is that it's only

putting in the amount it's not actually

putting

the actual balance so instead of amount

what should we put here take a

guess what we should actually put in

here is we should do

causeychecking.balance

okay that's what we want to do here

let's go ahead and do that

here as well so it's reading the balance

the entire time in that case

all right let's run it

and let's go 100

deposit

1000

deposit 5200

20 000 deposit 25 000 withdrawal 1000

or sorry withdrawal right

withdrawal let's say

19 000 it would draw boom the new

balance is 2200.

so

hopefully this should

so hopefully this tells you a lot about

how classes work

you know what you could do with them how

to then connect them to a ui and all of

those things because they make your life

honestly

a lot easier right and then you can use

them in a really nice easy way um

and they're just really useful and

you're gonna see them everywhere and

everything is a class like balance div

this is a class that's why you're doing

dot inner text

documents is probably like of a you you

get this document object model which is

probably like this class or this object

and you can do dot get element by id let

me ask you what's dot get element by id

is it a property is it a method or is it

a function which one is it

you should be able to guess this in like

three seconds three two one

if you guess this is a method good job

this is a method right because it looks

like a function but with a dot

that's a method so this document is a

class and then we're doing this dot

whatever method

um so everything just everything has to

do with classes and objects and

all this stuff and so this is why this

is so important for you to learn and

you know this this keyword is so

important to learn because this will

come so many places it will be so

confused what it was and you'll be

thankful that you did so many

class-based exercises and will still do

more because

like just doing one example is not

enough you have to do so many different

examples so many different exercises so

many different projects and then the

more you do the more it starts clicking

and the more you start understanding so

pattern recognition and programming is

one of the most key and underrated and

understated things that you could do

that will just like skyrocket your skill

set okay like intelligence is one thing

yes but pattern recognition is even

beyond that when it comes to con you

know programming even things like chess

and then you can build on top of it and

take it further

now the last thing i'll do for you is

we'll take this bank's class we're going

to go to our

javascript course

and then inside of here inside of

classes i'm going to create a new folder

and we'll call it

banks

class okay

and then in here i'm going to create a

new file it'll just be called script.js

and this file will have the entire code

okay and then i'll grab the index.html

so you have that to refer to as well and

you can always see it

go back here

and we'll add in

whoops oh jesus what did we do

what did i do okay i moved banks out of

the banks class out of the classes okay

cool now we're good

let's add in a new file here and we'll

say index.html

and we'll paste that html right here

okay

all right so now what you'll be able to

do is you'll be able to go to the home

page right and right on the home page

right here

you'll see lessons and in lessons you'll

see classes

it'll say bank with deposit and withdraw

methods and so this lesson will be

available for you you can click it

and play around with it right here okay

and deposit so you'll have the fully

working app with the final solution okay

and then you'll be able to hit withdraw

and take out any of the monies right hit

withdraw let's do 300.

boom

okay

boom

99

okay you'll be able to withdraw whatever

you want deposit whatever you want so

this app is there for you now and then

if you want to look at the code

obviously the code is going to be inside

of folder called classes it's going to

have banks class in there and inside of

there you're going to have this code and

then the script file

is going to be the main one where the

entire javascript is sitting there

waiting for you okay and you can always

use this to refer to your notes

run the app make changes and do whatever

you want okay hopefully that was

insightful and gave you some more

insight into classes and we'll be still

doing more stuff so i hope you're

prepared and excited all right now that

you got your classes skills up to a

certain level and we worked on how to

make a bank we also worked on how to

make a car class

now what i want you to do is you're

going to be taking it up a notch and

you're going to be building a street

fighter game and this is going to be a

really fancy game it's going to have

sounds and it's going to have the

ability to attack and heal and you're

gonna have ken and ryu and two fighters

fighting you're gonna be able to create

a player class a game class and you'll

be able to play the game win the game

and you'll be able to hit q a to attack

and heal from player one and you'll be

able to hit p and l

to attack and heal with player two and

there's gonna be a whole lot of stuff

you can do with classes and this game is

gonna push your javascript javascript

skills to the next level now for this

game your instructor is gonna be lance

so i hope you're excited stay put he's

an awesome instructor i love him to

death you're gonna enjoy it and i'm

gonna send it over to lance to show you

how to make the fighting street fighter

game let's go lance what is up guys it's

lance here and like kazi said i'm going

to be taking over this specific section

of the javascript course i hope you guys

are ready you guys are crushing it so

far and as you can see we're on a

separate repel from the course right

these are the topics that i want to go

over so the first one we have up here is

something called while loops you may

have heard of this when kazi was

explaining loops the ones that i know

that you guys know are the for loops so

take a look so with four loops my key if

you want to know the difference between

these two is you use four loops right

when

you

know how many times

you want to loop right

and for a while loop

right they do the same thing they both

loop but you use this when you are

not sure how many times

you want to loop right think about when

we use a for loop i use a for loop to go

through an array and loop however long

that array is we know that right but the

while loop we want to keep looping until

a condition

is not true all right so let me show you

what it looks like enough talk all right

for a while loop all you have to do is

set up is just this right the key thing

that makes this engine run is this right

here this is called your condition right

whatever you put here is how long you're

going to loop to so let's set up an

example all right let's say let num

is equal to zero right if i were to

console log num it would just show me

it's zero

but what if i say keep looping

while num

is less than

five

right

so that's how you can read this it's

actually really easy to read with while

loops you can say while num is less than

five keep looping so if i ask you guys

right now right here

is num less than five yes

right so if i were to run this piece of

code it would actually run forever

because when will num ever equal five

see

there we go so then we can say something

like this right while num is less than

five you wanna say

consolag looping

right and then after we say console log

looping we can also do a num

plus plus

all right do you guys remember what plus

plus does plus plus will increment add

one to the value of num so the first

time it's zero right then the second

time it's one two right and so what we

could also do here is put a comma and

write num

so if i were to run this code what do

you think we're gonna see in the console

over here give you guys five seconds

one

two three

four

five did you alright let's hit run and

we can see looping zero looping one

looping three looping four so how many

times did this run this run five times

right

so now we can switch it up

all right let's say

let's say let

num

2 is equal to 10 right but we didn't

know let's pretend this is a hidden

number that we didn't know right as long

as num is less than num2

right keep looping what if we didn't

know what num2 was will it still stop

yeah because once it reaches 10 right

the condition is no longer true so let's

hit run there we go 0 through 9. so

that's kind of how the while loop works

while the condition is true keep

looping so here's a here's another

example not as useful all right you can

say

let

and this will be closer to the activity

that we're doing let

finished equals false i'll say equal is

true

right so

if i said in this while loop finished

is equal equal to true

right

how many times would this loop if i were

to run it take a guess

if you said it ran infinitely you'd be

correct why is it infinite though answer

my question what do you think that's

because we're saying while finish is

equal equally true keep looping but at

any point did finish change no but if i

were to say in this while loop finish is

now equal to false

right

then we could say

run

and we'll just see one looping right

because it's going to console.log switch

it to false and then exit the wild

there we go so we looked at the while

loop that's pretty much it for that so

the next thing we have is add event

listener right here and if we were going

to talk about ad event listeners you

guys need to remember what the dom is so

what is the dom well

the dom

right

dom stands for what

document

object

model or model right basically the html

itself right so here doctype html and we

can select with javascript any of these

elements here so as you can see we have

our basic hello world text up there how

would i grab

this div

right with javascript all right can you

guys see it you guys remember

so give me five seconds

one

two

three

four

five awesome so

if you notice there's a little id here

that says play alright so what we could

do right is set up a variable you can

say

let

play is equal to and then how do you

grab uh an id from the dom well i can

say document dot get element by id

and just over here just say

play all right and if i were to console

log

play what are we going to see

exactly html

div element right if i wanted to get the

inner text

right

could do something like this

enter text hello world all right that's

what it says inside that div cool and

this is how we use the dom to get what

we want from our html right so

what if i wanted to add an on click to

this what did it cause it teach you you

guys remember and for simplifying and

for simplifying purposes we're actually

going to call this play div so you can

make a difference

okay cool so now

our variable that's holding our dom

element

called play is hello world so how do we

add an event listener the way that qazi

taught you right play div would be

something like this dot

on click right every element has an on

click attribute that we can access here

and we can say onclick is equal to

an anonymous function which just means

you know just means a function without a

name so if i say when i click this div

on the when i click on click of this div

we'll console.log

yoyo right so let's hit run

let's click hello world we should see

yoyo

oh i see it's because i did capital c

just to be lower case c

let's see now

run

yo yo yo

yo yo you got it cool so that's pretty

simple that's perfectly fine and i'm

just going to show you guys an alternate

way to do the same exact thing right so

this is the on click way right but

there's also

something called add event listener so

play div

so you could do is say play div dot

add event listener

right and then you can say

two things right so let's say add event

listener and you notice these

parentheses down here let me zoom in

cool these parentheses

comes from the add eventlistener method

so this is a method right

and it takes in two arguments what are

the arguments it's one

what

are you listening for here

well i'm listening for a click

then you can put a comma and then you're

going to put

a

function

like so

okay

so you do this es5 where you can say

function

and you basically it's what are you

listening for

and what do you want to do

when you click

all right so this time i want to say

console log

hey yo

or hey yo poo apparently all right so if

i hit run here and i click on this hey

yo

right so how is that different than this

it's just a longer way to add events

right the

like it's a long way than on click but

the benefit would be

instead of running a click i can write

other ones like key down key up you just

have to change what the event is

listening for

cool right so that's just another thing

a little side thing that i want to teach

you guys the main reason i wanted to

talk about event listeners is because we

can do something like this all right we

can say

document

dot add event listing right so what i

what am i adding an event listener to if

i ask you guys that question

okay take a look

so this one i added event listener to

the play div but this one i'm adding an

event lesson to

the document right so the document is

essentially the dom or the whole uh page

itself right so basically

if i say

right something like this

and write key down that is an event that

we can listen for

and then here i can say function

right

e

right

and then we'll console.log

hi

okay cool so

let's take a look and analyze this for a

second i'm saying document.add event

listener i'm saying listen for a key

down which is me pressing down on the

keyboard and then this function

represents what i want to do when i

press key down right i want to say

console.log high so let's hit run

and if i were to press let's say the

queue on my keyboard what's going to

happen

oh it's going to put q if i click that

let's click the app itself

hi all right i'm just going to click l

hi

i'm going to hit space bar

hi right whatever key i press down

it's going to run this function so

that's how event listeners work why is

this useful answer why am i telling you

well the main thing is e right here you

don't need to put e here but e

is essentially what's going to represent

our event or keyboard event right

so

if i say something like this if

e dot key right because each e has a key

attribute that we can call

e dot key equals

q

right

then i want to say console of

you

pressed

q

else

right i'll say console log

not q

okay cool so let's hit run again

if i were to press the spacebar once

again oops not there on the app

not q obviously it's not cute but if i

hit p

knock you what if i hit q

q so if you ever wanted to make your app

respond to your key presses we can use

document.ad event listener like how sick

is that right this is going to come into

play when me and you are going to make a

fighting game together where we can

press q do a nice punch we can press a

we can heal up so i'm getting excited

right but we're almost there that is

document.ad event listener right and you

can set conditions within that function

too so i like this because it kind of

like ties

everything together so

awesome so i hope you guys enjoyed that

one the next thing i want to talk about

is audio tags so let me get a second to

set up some sounds here for you guys so

that we can mess around with it okay so

i took a moment to grab some sounds for

you guys oops not packages sounds as you

can see we got fast heel quick heel

quick hit victory fast these are gonna

these are things that we're going to be

using for the fighting game activity

later on

but if you wanted to learn how to add

sounds to your javascript project we're

going to be using something called the

audio tag with our html so we're going

to need to go to our html for this one

and down below here we can go right

before the body or actually we can do it

outside of the body even and we can say

audio

like this

okay

all we have to do it's similar to

the script tags or your image tags right

we're going to add a source sorry we're

going to say source

is equal to sounds

all right and then we can just pick one

so let's do quick hit all right we can

say quick

quick

hit

dot

left

or actually mp3 doesn't really matter

cool

so that's the source and after that we

can had something called controls so i'm

just going to format it real quick

so we have source we can also do

style

yeah so for the style i just want to say

display none because i don't want to see

this audio tag

and then for

type

let's do an audio

mpeg

awesome

okay and then after that we can also

give this an id

so i'll just call this punch because

it's going to use that punch sound

effect and now that i'm looking at it

quick hit that web

is what should be here wav not mp3 so

make sure it's the same as the source

we'll hit run really quickly all right

don't see the auto tag good

and next what we want to do is head over

to your script.js

and let's think about it right so we

have this quick hit sound and kind of

goes like poo poo right but when do you

want to hear that sound right so that's

where the programming starts to come

into play i want to hear that sound

when i press

q

right so if i press q

after our console log

i want to play the sound so how can we

play the sound remember we gave this an

id right so if we give us an id how do

we grab

this element ah

now it's coming together so

if i want to grab an element you can say

document

dot get element by id

and just put in the name of the id which

i believe is just punch all right so we

got the element now but now we grabbed

this audio tag

how do i use it

well

to play audio we can just do this method

it's just called dot play

and if i hit run again

i press p

well not there i press p

not q right but if i press q

you heard that

all right it's going to play as long as

you press q

and a little thump sound that's the

little quick hit all right that's the

one i'm going to use for the project

itself so

you can set up conditions based on the

key that you key down that you press and

based on that you can play a punch or a

sound right so that's going to unlock a

world of possibilities for you guys we

could also set it so

let's say you want to add another sound

let's say if i don't press q i want to

hear something else so if you want to

add another sound i'll do is copy all

this right

place in that audio tag once again

help

don't forget to close it

there we go so that's the close this is

the closing audio tag for this one this

is the closing audio tag for this one

for this one make sure that closes but

instead we're going to say

victory instead of quick hit it is

victory and this is not wav this is mp3

so we got mp3 on the line let's hit

script js and when do i want that

victory sound to play it's when

i don't hit q so let's say

document.element

by id

and put in victory

vic

tori

and we'll hit dot play

this should work and let me just double

check that's what i called it yep

victory

awesome so let's see if this works

run i press q to punch you

you heard that and you hit p because

that's gonna be something else

hey so that's gonna be the victory music

when you win in the fighting game as

well but as long as i hit not q

i'll hit

i'll play that victory sound so if i hit

spacebar

all right i hope you guys can hear that

but this is super cool when i found out

about javascript sounds i was like yo we

could do a lot of different things now

right

cool so that is audio tag so i didn't

really write anything here but we are

using them mostly in our html

calling them with our javascript and

timing when do you want to hear that

sound so that's the very basics of all

of these things

we need all these three concepts plus

everything you learned previously to

make this fighting game app so

without further ado let's move on to the

next part alright i think you guys are

ready we can finally getting started on

your next project the fighting game i'm

super excited about this because there's

a lot that goes into this this is

definitely going to be a lot harder for

a project than the previous ones but i

think you guys are ready all right it's

going to go over all the topics that

we've done before especially focusing on

classes as you can see here so

before i explain what's going on i want

to demo the app a little bit as you can

see

this is our very minimal front end with

two players lance for player one kazi

for player two right it's pretty obvious

how this works if i were to press q

lands attacks if kanzi presses q i mean

p he attacks as well alright so let's

see what happens if i press q right now

oops not there

on the click on the app thank you

there you go you hear that little sound

effect

and it hits and does damage to qazi and

it updates the dom live which is sick

all right what if kazi replies with by

pressing p

there you go i did a little bit more

damage than him but we'll see we'll see

all right let's say kazi wants to heal

up

heard that there we go i can heal up as

well

and that's pretty much the game we can

kind of just go at each other one person

on the right side keyboard one person on

the left or you can just play by

yourself like this

[Music]

hey so it looks like i win this round as

you can see lance wins right here and if

you wanted to reset just click this nice

button over here boom so we're back to

100 health we could go again

[Music]

now cozzy wins this time so that's

pretty much the app all right it looks

like pretty simple but there's a lot of

things we actually need to keep in mind

so i hope you guys are ready right as an

added feature we can hit the simulate

button

and look at that kazi wins the

simulation right it just basically runs

through all the commands and once

there's a winner it'll get print out who

wins

so that's pretty much the demo

now it's time to get through the

exercise you guys ready awesome

so to get to the exercise when you hit

run the javascript course you just have

to click fighting game right here the

exercise

and you should see the same layout if i

were to press q or anything like that

it's not going to work it'd simulate

nothing all right we're going to add

those features ourselves and if i go to

this rupple here

right this is the same thing this is

basically the exercise just

ported onto an independent ripple for

your guys's testing purposes so

i'm going to link it to you guys but hop

on a separate rebel to get started on

the exercise i'm going to be on here

explaining to you guys how it works you

ready let's go alright so you guys

finally made it here to the fighting

game app and now i wanted to explain to

you guys how it works give you guys a

little bit of a tour just so you

understand what the hell am i going to

do to make this work so we saw a couple

things right you saw me press q to

attack right you saw me press reset

right you could probably think in your

head how you're probably going to do

this but luckily for you in the script

js

right you'll see all the instructions so

i walk you guys through don't worry

so again make sure you fork this

specific rebel fighting game project

right so that you can test your code

here and not mess with the javascript

course if you forked that right and then

when you're done you're just going to

copy paste your code to the repo so

we'll meet up back there make sense cool

so this is the fighting game app right

this is to create an update game

function that will update the dom with

the state of the game what that means is

when i punch qazi he loses health we

should update the html now there's two

classes we have to create a player

and a game right you guys made classes

with qazi before remember so that was

like the car right and the car can drive

it can honk

right what is this class this class

he can strike or heal and that makes

sense for the player right but then

there's a class for game

the game is going to represent the whole

game itself so what can the game do

play

check if it's over declare the winner

and reset so i hope that makes sense to

you these functions are hard-coded into

html so don't change their names keep it

as it is

and here you're going to find all the

div ids that we're going to be using

there's a couple all right let's play

result the names and the health so let's

take a look at the h the html just for a

second take a look around as you can see

very bare bones right this is the image

of ryu here here is a div called player

controls so let's why did i go here it's

because of this id so there's an id

called

result right and that's going to hold

the winner of the match right so

remember that you saw that lance wins

over here

that's gonna be with the result div so

if you look scroll down to the result

this is the div that's gonna hold that

name

okay so if you're ever wondering what

the hell is this lance take a look at

html and see if you can find that same

div

cool but lucky for you and the exercise

we grab all the dips for you right so

the names should make sense it's pretty

easy to read the play button is a

variable that holds the play div

right the name div holds the player one

name uh-huh cool

awesome so now for the meet right the

actual factual functionality of the app

right

this is called update game right the

point of update game is exactly what it

sounds like update the dom with the

names

and the latest health of the players

right so right now it's defaulted to 100

and defaulted to player 1 and player 2.

that's just based off the html so if i

go to

player 1

right here

how do you like take a second to think

about this

how would you guys grab this div

and change the text of it

to the player

ah right it's getting really complex now

but it's not as complex as you think

right

so we want to be updating this to lens

and this takazi or even your name and

then within update game we're also going

to think about

when do we want to stop updating the

game and just declare a winner right

what condition will we need to do that

right so when we update the game

we're gonna need a condition to check

if the player health is less than or

equal to zero because if it's less than

or equal to zero

should we keep playing the game no we're

done so right

so if this hits zero or is less than

zero we can declare a winner and declare

winner is actually another method all

right if you scroll up you'll see all

the methods that we need to make

cool

so the very first thing besides update

game once you have that working we need

to start creating our classes so what is

a class guys can you remember a class i

like to call it a template for creating

an object right so this is the blueprint

of that object what kind of object are

we making here

exactly a player object so

in the constructor

we have to think about what are the

attributes of a player object so what do

we need we need a name

we need a health and we're going to need

attack damage right that attack damage

if you guys don't play any video games

or unfamiliar that just means how much

damage will my punch do to you

all right

so we can leave that as attack damage

right

and make sure that this is all passed in

the constructor because we are going to

do that ourselves later

cool so for the strike

this is a function within the class and

remember what that's called exactly it's

called a method right so this is the

strike method

and keep mo keep note of what it takes

in takes in a player

an enemy or attack damage right

before you get all worried

what do you think the strike function

does

exactly what it sounds like you're going

to strike somebody

right

so

when i strike

kazi

we can make him lose five damage points

or a health point so this should be like

95 right but we want to make it random

you guys know how to make random damage

right so that's why the first

instruction here is get a random number

between 1 and 10

and that is the damage amount so think

about that how do i get a random number

hmm

right

think way back right

actually not even that back you guys did

that earlier in another project

so get a random number between 1 and 10

that is your damage amount

so now that we have a random number

that's the damage amount

what should we do with that amount

exactly we should subtract

qazi's health with that amount right so

subtract the enemy health with the

damage amount right so how could we you

know change the enemy health

by

subtracting the damage amount

right so play around with it that's why

that's why i want you guys going

separate rebel it's easier to just play

around and test it right i don't expect

you guys to be like i got this lance

right for me it's going to be

incremental you got to test stuff out

all right feel it up so subtract the

enemy health for the damage amount and

after we do that you

you technically you did damage right

that's correct but i want to see it on

the html itself on the front end right

so we need to update

the dom somehow so

guess what then you're going to call

update game which is going to update

everything with the latest stats

so that's why

a lot of the functionality comes from

you making sure the updating game works

properly

cool so after you do some damage after

you strike kazi

you subtract the health you update the

game and then just return a message

saying

uh lance attacks qazi for this amount

right not too bad

right

now

if you understood that the heel is going

to be very very similar

right so remember a heel

is going to restore some health back

right so we don't want to make heal

overpowered so instead of 1 through 10

heal is a method that takes in who is

healing

right so if i put in let me put an

example here

heal

uh player one who's healing player two

or player one

player one you guys are killing it so if

you said player one we're good to go how

does heel work well the first thing

we're going to do is get a random number

from one two five exactly so we take

that number one to five and store it in

a variable we can call it hp amount so

we have amount what should we do with

that amount

add it to the player's health right so

if i got my num random number was 3

i need to add 3 to the player's health

so something i want you to start

thinking about is right

how do we get the player health lance

right

well you got to think back on when you

make a object from a player class

how do you get that health

and then how do you want to pass it down

right because it takes in a player so

how do we get that player and how do we

get the health

cool so after you added the health to

the player

guess what we got to update the game to

make sure that our html is up to date

okay and when it's done just return me a

nice message that says lance heals for

two hp

do good so far

great because you're done with the

player class that's it only strike and

heal as you can see

awesome

so

with the player class done there's also

the game class right so if again class

template or blueprint for creating an

object what object are we creating in

here we're creating the game and all the

functionality for it so in the

constructure constructor the constructor

right the attribute that it needs is

just is over so if i ask guys what do

you think is over

means

right it looks like it's defaulted to

false

alright what do you think it means

all right take a second

one two

three four five

is over represents if the game is over

so if the game if so if is over is false

is the game over

nah it's not over yet if it's true

though the game is over

okay

cool that's all you need to know by

default it's going to be false because

if it's true that means we finish the

round and if i ask guys when do you

think the game would be over here

yes this would be if one of us

health

is below zero or equal to zero so as

long as it's not zero or equal to zero

keep playing cool so if you got that

let's talk about our first method here

this is called declare the winner or

declare winner notice what it takes in

it takes in is over that's interesting

okay it takes in player one

and player two right if you look at the

description if the game is over

and a player has zero health we need to

declare who the winner is and that's

what this function does

cool so

all i want you to do is just create a

variable that's going to hold the

message

and

if is over is true why do i want to

check for that because if if if is over

is true then that means the game is over

but we don't want it to just be that

we also want it to be and

so what's and in programming that's

going to be something you want to think

about

and

player 1 health is less than or equal to

0

then update the message

to player one wins or lance wins

then we're gonna need an else if if is

over is true

and

p2 health is less than or equal to zero

then update the message to kazuwins or

p2 wins

and just for fun here if you look

underneath we need to play the victory

sound which i totally forgot for the

strike we also want to play a little

sound too right but you don't have to

worry about that just yet

that's gonna happen when you press

buttons

but when we declare the winner

there should be a nice victory sound

okay and after that just return message

variable

that's the clear one

keeping up so far feel free to rewind a

part of the video just to hear me

explain it one more time sometimes you

just need it more than once and it

clicks all right

and don't worry too if you're totally

lost

there's going to be a solution where i

explain how the code works

awesome

so

here we have reset

reset is exactly what it sounds like

let's say we finish the game and it's

over

we can hit reset to put back the hp to

zero not zero sorry 100 right so reset

is going to set the health back to 100

and what else should we do

exactly

we should set is over from true to false

or just make sure it's false because

then when we reset the game is ready to

go yeah

cool

another bonus thing is usually there's

going to be a text here that says lance

or causey wins

we want to clear that resolve div in our

text so that doesn't show there's a

winner right because it shouldn't be

wondering if we just started or reset

yeah

cool

awesome then there is this play feature

right

that's the one where we press simulate

and it's gonna just run through

all the commands and just generates a

winner randomly not randomly but based

off the commands that you put

so

this is where that while loop comes in

and notice something where it says while

exclamation point

this is over right so what does the

exclamation point mean if you don't know

what the exclamation point mean that

just means not right

so

when not this is over or in other words

if this is over sorry in other words

as long as this over this is over is

false keep running

right

if it's true then it's going to stop

so basically once is over is true

no more while loop

right keep looping until is over is true

if this is confusing you you can still

write it as that as well you can say

false like so and it would still work

the same right this is just another way

to do the same thing

amazing

so like i said once is over is true the

while loop is broken

then we declare the winner right this is

the simulation part right that's nothing

to do with us pressing or clicking the

buttons this is if you got lazy you just

want to see who would win click simulate

awesome so once that while loop is done

run that declare winner method

after that here i want you to set up the

players or you can say let player 1

equal 2 and then how do you set up a new

player object from the class you tell me

all right so put that over here then we

want to save that original player data

right so if i said uh let player one

equals you can say let p1 equal to

player one i just want to set a copy so

that we can reset without

um worrying about

you know

the original health

so there's that

next create the game object from the

game class it's the same as this one all

right how do we make a new instance of

the game class

and then we can initialize the game by

up saying update game right because when

you put in lance and qazi as the players

it's not going to say lance and qazi

here unless you call

update game

right

so make sure you call update game over

here

awesome

over here it's the same thing like we're

doing

up at the top here except we're just

saving the state of is over

okay

now this right here line 148

we're going to add a on click

right listener that's going to run the

play method

all right so think about

how do we set up an on click

what uh div element are we gonna use

from here

to hit the play button or it's the

simulate button

and make sure that it runs it right

that's all you need to do for 148

and for 151 if you're still listening

right you're going to add functionality

where we can press

a or q to do different things so if you

remember the prep section that we had

earlier this is where it all comes to

play so here this should look familiar

add event listener key down function e

right

here's the trick if you press q

and the enemy health is greater than

zero and is over is still false then

call the strike function or method sorry

strike method and after striking

play the attack sound so here's the

audio tag section coming up again and

you might be asking lance

there's audio here well if you look at

the index

right

scroll all the way to the bottom you can

see i already set up the audio for you

you just have to play it so how do we

play audio sounds think about how we did

that

all right grab the ids

and you hit the play method to play the

sound it's up to you guys to tell me

when you want to play each sound so map

out the sounds to what you want

make sure you get the heel in there this

is for keel and this is the player two

controls

and once you have that you should have a

working fighting game so this is

definitely a challenge i'm not gonna lie

to you guys but if you do this you can

pretty much make whatever game you want

and i think you guys are up for the

challenge so

take your time with this rewind what you

need to and if anything we can look at

the solution and do this together so are

you guys ready i know i am let's get

started

all right so this is the solution let's

walk through how to make this fighting

game app together so are you guys ready

and at any point it's starting to all

click

feel free to pause the video and see how

far you get before i catch up to you so

this is it this is the fighting game at

the moment nothing works i'm pressing

buttons and nothing is happening so as

you can see this is the fighting game

and if as a reminder the main

functionality of this game visually is

from update game right it does exactly

what it sounds like it's going to update

the html or the dom with whatever's

happening all right so we can see it

the main core functionality is going to

be based on these two classes that we'll

make so think back to when you made a

bank think back to when you made a car

with qazi right we're going to make a

player now and we're going to make a

game all right so

what i'm going to do we're going to be

unconventional we're going to start with

the classes first so that update game

might make sense right we're going to

start with by making the classes

cool so let's scroll down to the class

player right this is the part that you

guys should be familiar with when i make

a new player it should look something

like this

and we have to pass in qazi the health

and the

attack damage which is just how much

damage will cause this punch do that's

that's what seven is standing for right

cool

so as you can see this is where the name

goes the health goes and the attack

damage goes and then from here we put

that for each

property of an object right so how do i

get if after i create a new player how

do i get kazi's name you're going to do

kazi.net or kazi right so

let's not we don't have to make any of

the functions i just want to showcase

you how this works so if we scroll down

let's find where we have to make the

players

who will create two players using the

player class right

so

what we have to do i'll do is say let

player 1 right you can call this

whatever but i want to call player 1

equal to

how do we make a new instance of an

object we can say new

the class name right so capita capital p

parentheses and then whatever we pass in

so a reminder what do we pass in we need

name health and attack damage okay so

let's see so we're gonna need name which

will be player one will be this time

we'll make it quasi right

and then the next parameter is health

we'll say 100 and for attack damage

let's just say 10

so now that that's there this is player

1. if i were to console

log player one what am i going to see

guys

and we see

there you go there is our player object

with name health and tactic so if i say

player1.health

right we should see

100. cool if i wanted the player one's

name

that name right so that's why

in the example we have something like

this

let's see

over here yeah that's why i said player

one a name

is the name or kazi because that's the

name of the variable

beautiful so at this point you guys

should be able to make player two so i

don't make player two same thing let

player two

is equal to new player

lance

we'll say 100 as well and we'll also

make 15 to make it fair well sorry not

fair that's not fair at all we'll make

it 10. sorry

beautiful all right so with that said

those are our two player classes right

so with coding everything's a pattern

and once you understand the pattern we

can replicate and do what we need to so

this is how you create two players from

the player class how do we create a game

object from the game class

okay

cool so

if you were saying like game equals new

game

right

is that it

right well if you're one they're not

sure if this is it we're gonna look up

and see if we need to pass anything in

the constructor

nothing so

this is it for the game class right and

if i were to console log the game

right

let's see

what we find out we say the object and

only attribute that it has is is over is

false right as a reminder what is is

over mean right basically if is over

equals true

the game is over if it's false i can

still punch quasi he can still punch me

back alright we can keep playing so

that's what the game is so if i were to

if i wanted to see the state of the game

i can just say console log game dot

is over and it's false so is the game

over false it's not over

awesome

so that's the basics i initialized it

like this we're going to come back to

this but this is my review for the

classes

cool so now when i say p1 dot health or

p1 that name or game dot is over you

should know what i mean

cool

all righty so now that you've got your

refresher on how the classes work we're

going to make the core function that's

not in any class it's called update game

and again it's going to update the html

to the game right so if you look at the

comment here

we're going to update the dom with the

names and the latest health of the

players what do i mean by that let's

break it down by the names so with names

where are the names on the html do you

see it it's player one

and player two right

i wanna change this to the names that i

put in so if you look all the way down

player one is kazi so this should be

changed to kazi alright so how do i

change that to cause

right to break it down step by step

first i need to grab

this dom element all right so how do i

grab the player one dom element

so lucky for you

all the elements that you need are up

here you're just going to have to

examine each one and think about what

you need and they're pretty easy to read

in my opinion so which of these

variables contains the name

dom element

all right i know you guys see it it's

number 38 p1 named it is equal to p1

name right if i were to console.log it

just to prove it to you guys

p1 name div hit run

boom there it is html div element and

then how do i get the player one text in

there right do you remember

think back to what kali taught you he

said dot inner text

and i can see player one so again where

is this coming from we are grabbing it

from the dom which is right here and you

can see it highlighted p1 name

the inner text of this div

is player one okay cool so now that we

know how to get this player 1 we need to

determine what we want to change it to

right so

in this function line 44 we can write

p1 name div

right and what do i want to change about

this div do i want to change the whole

entire div

no just the inner text so to change the

inner text you just do it enter text

again

and to actually update it or change it

you say equals and then if i say

something like dog this is going to say

dog right but it's i don't want to say

dog i want to say kazi

and i could just hard code this to kazi

this is still technically correct right

but what would be more accurate

is if i get it

from this object player one object so

how do i get the name of player one

right so you see how

the code can be written in a way that's

readable so if i want player 1 right

i could write player 1 here that would

still work but

this is the key here this is the

parentheses in here this is the argument

i'm passing player 1

as p1 so what i'm basically saying is

player 1

is

the same as

p1 so whenever i say p1 i'm talking

about player 1. same thing with p2 okay

so in the inner text here if i say p1

this is what is the data type of p1 is

it a

string a number or an object

i'm gonna give you guys five seconds one

two

three

four

five if you said object you are correct

it's the same as the player

object that we created before so if this

is the object what properties does this

object have and which one do i need

right

i need

the name so i'll just say p1 dot name

and there we go

all right and i'm just underneath this

i'll call update game right here i'm

going to move it later but if i say

update game and i say pass in oops

actually no i can't do that and you go

back

cool if i were to go down here to prove

it to you

let's see

you want to be calling

update game here so in line 143 this is

where we're going to call update game

and we're gonna pass in

player one

or actually no we're gonna do this sorry

let me start over

so we're gonna come down to 143

and over here in 137 we're gonna save

that player data so p1 is equal to

player one

and p2 is equal to player two

okay we're doing this so that we have

the original player data

all right so when we reset it's going to

be easier so

now like i said before player 1 is the

same as p1

cool so we want to start the game by

updating it

and we can put p1

p2

and we can say

the game

i think was the third variable

game state oh yeah game

dot is over

perfect

okay now hit run here look at that quasi

it's kazi now right how is it kazi did i

write just kazi there nope because i am

saying an update game change that inner

text to player one's name all right like

i said before we could do dog here and

if i hit run

it's going to be dog

cool

and again like i said

kazi would still work in this scenario

right but it's not what we call dynamic

right it's hard-coded quasi right

i want it to be whatever i put so if i

put p1 that name here

it's qazi

but if i go back to

this instance in 134 if i change this to

kevin

hit run

now it's kevin see how it's dynamic

depending on what it's like kind of like

when you start a video game and it says

enter your name here the game will be

updated to say that name all right so

that's what we're doing all right so hit

run

cool so if i ask you guys how can we

put in player two's name

how can we put player two's name what

would you guys do

you guys got the pattern it's gonna be

p2 name div dot inner text is equal to

p2 dot name

boom that's it

awesome so what about the health well

the health

right we're gonna what we need to start

thinking about what div

holds this health right let's see if

there's anything that can help us here

all right if you're not sure we can also

look here so in the health

it's going to be the p1 health right so

we have to grab that element by its id

and we already did over here

right p1 health dip so

following the same pattern we can just

say p1 health div dot inner text is

equal to

what we're going to put is the p1 dot

health

all right same thing here p2healthdiv

dot in our text

oops

dot enter text

is equal to

p2 dot l

awesome so this isn't so bad because

this is it this is what's actually

making it so we can see what's going on

after i punch quasi or he punches me

back

cool

so

now the next thing is

if i punch qazi his health will drop to

like 90 or whatever

okay so if it's 90

are we still playing yes or no

yes so if we're still playing right that

means we can keep going at it but if

my health

is zero can qazi still punch me no he

shouldn't be able to i'm already done

right so

we can set a condition

to make it so it stops

updating the game and we can declare a

winner right because that means the game

is over so

we can clear a condition like i said so

if

the player health is less than or equal

to zero then set is over to true

right so basically told you what's right

for the condition

so how do i get the player health again

p1 dot health

okay you're right

health

right and what do we want to check about

the health we just want to say p1.health

right what we want to say is if

p1 that health if kazi's health is less

than or equal to zero

right then the game should be over

right but what about my health if my

health is less than or equal to zero

right can we keep playing no

so what am i really saying then um what

i'm saying is if either player's health

is equal to zero right

so we can say this or right here this

means

or

p2.health is less than or equal to zero

so let's read this out fully together so

this is saying if kazi's health is less

than zero or equal to zero

or if lance's health is less than or

equal to zero

that means the game is over but is it

over by just writing this if statement

not really right what we need to do is

take the game state right

or in other words take game dot is over

right and set that to true and then we

can update the game state our game state

is what we passed in here

game state to equal

game

dot is over

right so it's like it's called

transitive property i'm saying this is

now true and now game state is also

equal to true right

cool

now

if you remember the solution and the

demo

when kazi beats me right it's going to

say kazi's wins over here in this area

right here where my mouse is right

so what we need to do

to make it so that messages displays is

find out which of these holds that

resultive right if i go to the html

let's look at the html where are you

over here 989 it's empty right but we

want to populate it with a message that

says kazi wins right

so

that's what this update game is going to

return

right so we're going to say

result dot inner text

right where am i getting result from i'm

getting it from over here

all right it's actually called result

div sorry

and how do i change it to the message

well the message is can be like kazi

wins

but that's not dynamic guys

if i put kazi wins here

and i beat qazi

it's gonna still say kazi wins and

that's not right so

what we need to do is make a dynamic by

saying is equal to

game

dot declare winner right and pass in the

arguments let's pause them

you might be wondering lance what the

hell is declare winner well don't worry

declare winner if you remember up at the

top here

it's a function or method that comes

from the game class and we haven't made

declare winner yet so don't worry about

it just know that we have to call it

right here

okay so declare winner and if you look

at declare winner all right sorry for

moving around it's going to take three

properties it's gonna take the game

state which is game is over right it's

gonna take

p1 and p2 right kind of like

transferring this over it's like uh this

guy was doing stuff and then now pass it

on to the next task right

declare winner his job all it is is to

let us know that handles who the winner

is right

update game is just updating the game

declare winner is telling us who

actually won between the two

does that make sense perfect and the

last thing we want to do in this if

statement we can just say return the

game state

perfect

okay that should be good then that's

update game for you

so let's hit run

perfect so now we got quasi lens right

we're making progress on our app already

cool

awesome so now we need to do

strike and heal and strike and heal is

from the player class right so remember

this is the player object and methods

are functions within the class right so

when i never think about methods methods

are just what that object is supposed to

do so what is the player object supposed

to do it's supposed to strike an attack

right now it can also heal up so that's

why these two methods are strike

and heal all right you guys are doing

great so far right that first function

wasn't bad right this thing should be

more familiar this this method

okay

it's kind of like look at this as like a

big review of everything you learned so

far and don't worry if it doesn't make

sense take your time pause the video

take a break take a walk right the cool

part about this being a youtube video is

that you can take it at a pace that you

want

so

with let damage amount right so this is

the comment here strike is attacking an

enemy from a random number between zero

and your attack damage bonus okay

so what we're going to need to do

is

get a random number between 1 and 10 and

that is the damage amount right so let's

do that so how do we get a random number

guys do you remember

to get a random number we're gonna use

math.random

right and what i wanna what i wanna do

is store that in a variable so let's

make a variable let's call it damage

amount all right and we'll set this

equal to

math.random

right

and then if i do times

10 that's going to give me a random

number between 1 and 10.

right

and more specifically every single

number between one and then so that

means 1.5 1.6 1.7 1.10

do you want to do

0.5 damage to causey or lance no so

there's two ways we could go about it we

could do

math.ceiling to round down or math.floor

sorry math.ceiling to round up and map

that floor to round down right and if i

want to make it to 10 right let's use

math.seal so math.seal is how you use it

put that in parentheses

and there we go so

if i asked you guys what does line 75 do

it gets a random number between one and

ten

cool and we store that random number

let's say it's seven and put it in

damage amount

all right

so how can we take that damage amount

okay

and subtract the enemy's health by it

right so let's say i'm quasi

i'm punching or striking lance myself

and for seven damage right

how can i reflect that on

lance's health that i lost seven damage

well we have to subtract it with the

damage amount so to get the how do i get

the enemy health then that's probably a

question you have

well again you have to ask yourself do i

have access right that's kind of like

the key here do i have access to the

enemy health if i look at the

parentheses here

yes i do it's an under enemy so if i

were to console log enemy and test this

function out right that's going to be

the player

object right or the one who's getting

attacked

in this case me

so what i could do is say enemy right

and how do i get the health of a player

exactly.health right this is not new you

got it guys that health right and how do

i subtract damage amount by it well

it's going to be minus equals damage

amount right subtract enemy health by

the damage amount

not too bad right cool

all right so then

if i did the damage already what should

i do next

i should update the game because kazi

can punch me

but it's not gonna get reflected on here

unless i

update the game so let's update the game

by saying

by saying um what's it called

player

not player

then we could say

oops

player

then we could say enemy

and then we could say

the state of the game which is just

going to be game state right or in other

words game dot is over

perfect

all right and the last thing to need to

do is return

a message

right and basically the message is going

to say like qazi attacks lands for this

much damage right and if you remember

there's something called template

literals where we can make this dynamic

we could say player dot name which is

going to be kazi attacks

template literal

lance and get the name

for and how do i get the amount of

damage well luckily thanks to the

variable name you can just say damage

amount

perfect

cool

so we should have strike and i know

you're gonna say attack damage is not

used but i'm gonna come back to it if

this makes sense to you guys

okay cool

all right so let's test the function out

and see if it works

so we can hard code that function and

call it right here remember p1 is player

one so how do i use the strike method

of this player right if you remember a

method it's just a function inside of an

object so we could just say dodge strike

and remember i can't just write dot

strike i have to pass in what

i have to pass in

dun

dun the player the enemy and how much

damage

right

so

what i'll put here is

player one right that's the player the

enemy is gonna be player two and the

attack damage is going to be 10.

remember i'm not using attack damage yet

right

so let's run this function and see what

happens boom 91 right so how much damage

did kazi do to me he did nine damage if

i run

he did one damage to me right see how

it's a random number each time the

strike is working perfectly right so

we can do console log two we can

console.log p1 strike to see what it

returns to us

is it run

92 and it says qazi attacks lance for

eight all right so we are missing

something

that's why you always want a console log

to make sure you're not missing anything

so let's see for

eight didn't say damage all right so

that looks more

uh like an actual game message so it's a

run

kazi attacks lands for nine damage right

so this is perfect this is the strike

function already set up right cool so

now let's talk about uh the attack

damage argument

so remember i'm not using this

right

but this has the same name as a player

as the player attack damage right so at

the moment we're getting a random number

between 1 and 10

right but you guys should be able to

understand this if i remove this 10 and

said attack

damage right what did i just do

what's going to be the random number

if you said i don't know right

that's going to be true because it's

dynamic right why is it dynamic because

if i put

let's say i put

25 here right as attack damage

what that means is

if i go over here

i'm now getting a random number between

1

and

25 or whatever i put as attack damage

let's see if that's right let's hit run

11 damage right that's big boy damage

that's five all right 13 right nine all

right two right 13. there's a lot of

ways to get a number but it can go as

high as 25 if you put it there there you

go that's a big one

23 damage

right

so

what i'm saying is

if i based it off now make it even more

dynamic instead of just writing 25

i want to say it's going to be based off

p1

dot

attack damage right

so now what is the random number between

all right take a look at player one the

random number now is between one and ten

again

right so this is the place where you're

going to input your character stats

right so in the video game you put the

player's name you put the health and

then you could say qazi can do uh 50

damage right let's hit

run run 14

19 23 48 damage right so as you can see

this is what controls how much den so

there's a lot of variation now that we

added to the game right you could give

someone with a thousand health and

someone else a thousand damage if you

wanted to right but for simplicity's

sake i'm going to keep it at 100 and i'm

going to keep this at 10. okay so let's

hit run and now it's back to 1 through

10.

cool

and you also know that this piece of

code is what makes me or makes quasi do

the punch all right if you wanted to

change it around to me doing the punch

back to kazi you say p2.strike

change this player to p2 change this to

p1 and take in

player 2's damage

yeah

cool so the way i would like to

understand this app is remember the bits

and pieces of this app and figure out

ways to we can put it together and when

we want to put together right so

we don't we can erase this because we

get how it works now if i hit run right

nothing happens

right because i only want to call this

strike function at a certain point but

we'll get back to that later so that's

the strike

right i'm gonna move a little bit faster

because the heel

is actually the exact same thing except

no one takes one argument just who the

player that's gonna heal right so if

cause is healing

we're going to put causes information in

here

okay so the first thing is get a random

number between one and five let's do it

so let's call it hp amount and let's get

a random number between one and five

well that's going to equal

right

math.random

times

5 right but this is going to be 0

through 5 and it's going to be the

decimal places so we want to say

math.seal

right

and there we go

all right that's the hp amount how do we

add the hp amount to the player's health

well we can just say player right if you

remember

this up here

it's going to be plus equals

player

dot health well not player health sorry

player dot health sorry is going to be

plus equals the hp amount

okie dokie so we got player.health plus

equals hpm

cool

so after we

updated the health in the background

right we need to update the front end

with it so

our phone was only a way that we could

do that it's with update game so update

game it's going to take in

the player right

and also

p2

and also game state

all right which is also just game that

is over

perfect

okay and then we're gonna return a nice

message so that we could see it which

can be similar to before which is

backticks

right

it's going to read qazi

heals for

5 hp for example so to get kazzy's name

we say player.name and then we can say

heals for

the hp amount

and then you could say hp exclamation

point perfect now let's test if this

works

okay so

to test if it works we're gonna get p1

how do i get the heal method

dot heal

what arguments does it take

it's gonna take in who's healing

right and i hit run

i healed for 103. let's see if our

message works

so let's console log the return

kazi heals for three hp that's perfect

all right 101 104 101 right so this

piece of code

is how a player can heal right

so there you go and with that if you

wanted to make player two heal just say

p2.heal and p2 right

the benefit of making something dynamic

is that you can heal like this

okay

oh i see i see

speaking of making a dynamic i made it a

little too dynamic it's a good thing we

tested this

so go back to the heel

yes this could just be p1 p2 right

because those are the variables that

hold the player names so now i've hit

run there you go 100 101. now let's only

lance heals for four

so remember this is how a player can

heal depending on who wants to heal you

just change it from p1 to p2

so erase that

and guess what guys

we finish the player class let's go so

the player class is now done and let's

say the game is pretty much half done

too right we already can strike we can

also heal

cool

so now

let's work on the game class

all right so remember refresh on the

game class the game object represents

the whole entire game and within that

game right we are using strike and heal

right but the only thing that we care

about with the game is checking if it's

over

right which it should be false at the

beginning

uh declaring the winner right after we

update the game we have to say like oh

qazi wins or oh lance wins right we also

want to be able to reset that's what

this button is for

but let's say we're all at zero hp if i

hit reset we should be able to restart

our health back to normal

set is over back to false and then we

can fight again

right

then there's also this bonus function

called play right and play

is gonna make it so that we can simulate

the whole match okay

so you don't even have to play the game

you can kind of just simulate what would

happen right by pressing the simulate

button

okay

so let's work on that and if we do that

the game is pretty much done

right we just need to add like little

details like sound effects so

starting with declare winner if the game

is over and a player health has zero

health declare the winner right so let's

do that let's create a message variable

that's the first thing right here so

let's say

let

message

and that's it

okay

it's going to hold a different message

based on the condition right so that

means

if you look at this it says if is over

is true

and

qazi health is less than equal to zero

then update the message variable to qazi

wins

right so

there i kind of tell you guys how to

write this exact thing you say if

right

code block

and read this and translate it to code

well if

is over

right

is over

equals equals true all right and how

come i don't have to write game dot is

over

right

well take a look do i have access to

just is over yes i do right over here it

takes in is over p1 p2 so i can just

call it freely like so

cool so if is over is true

right

and

p1 dot health is

less than or equal to zero right in

other words if the game is over

and causes health to zero right

then i want to make the message right

update the message to say

backticks

p

2 dot name

wins why do i want to say p2.name wins

all right think about it for a second

if the player wants health is zero

who actually won

player two all right kazi's health is

zero then i win lance wins all right

next is the elsif right i'm going to

write it just right over here

else if

which is the other what's the other

scenario in this case well the other

scenario is is over

equal equal true

and right and means both conditions have

to be true

p2.health

is equal less than or equal to zero

okay and if that's true right

we want it so that the message

says

p1 wins

yeah so the message is gonna say p

one

dot name

wins

perfect okay and then if i want i could

just take this and put it over here

perfect

cool and after that we also have a

victory sound that i want to play so

if you look in the html

and you remember the prep course that we

did together all the sounds are set up

right here right we have p1 attack p1

heal p2 attack p2 heal and victory so

and all the sounds are loaded up on here

as well so we want to play is that

victory sound over here

so

let's play that victory sound

and remember to play the victory sound

we just do document

get the

element by id

which is just going to be

victory

and we're going to hit dot play

right

and then

since we have the message variable we

can just say message

all right make that really simple cool

and now we can declare the winner right

this function is now up and running

let's see what's what's going on here a

message okay good this function is now

up and running

and if you remember update game function

let's see where is it perfect in update

game function

i said game

dot declare winner because that's the

method of the game

and we passed it in and that's going to

hold the message so what is going to

show up in the inner text of this

resultive

exactly it's going to show lance wins or

kazi wins

okay

cool

and we can't test it yet until until um

you know we get the actual attacking

functionality up and running

so why don't we do that

so before we get through the reset and

play we're gonna pause this for a second

and we're gonna make it so that we can

actually punch

and heal right so let's scroll

all the way down to the bottom

right to the player one controls this is

the meat of the project right so if you

remember the prep i'm using document.add

event listener key down right it's

listening for me pressing down on my

keyboard

uh the specific thing is if i press the

q button

then i want to be able to attack right

so let's set that up

so if right and how do i get the key

for q right it's going to come through

this e parameter right here which is

like your keyboard event so if my

keyboard

dot key right is equal equal to q that's

basically what i want to say here so

i'll say if

equal to

q

or if i press q

and right p2 dot health

is greater than

zero

and

the game dot

is over is equal equal to false right

there's three conditions here why do

they matter because i want to be able to

press q

but i can only press this q

if

you know player 2 is still alive and the

game is not over otherwise i'm just

going to keep beating up a dead horse

right we don't want to do that so

let's put the code block in here and

after striking right play the attack

sound that's the comment that should go

in here

right after striking then play the

attack sound well how do i strike well i

showed you guys how to strike to strike

you just have to say the person that's

striking which is player one

right

uh put in who's striking who's the enemy

and we wanna make sure that takes in the

attack damage right we're making a

dynamic here

cool

so let's hit run

if i press q

oops no click on the app press q

hey look at that

we're doing some damage here so if i hit

run again to reset it for now right i

also want to make a sound you know just

to put some impact

right so

if you look over here which one is the

player one attack it is p1 attack right

awesome i made the names nice and easy

for you guys so it's not too confusing i

know it's a lot right but you guys if

you guys made it to this point you're

doing great so far

so how do i grab that element you can

say document

dot get element by id

you can say

p1

attack

right

and you can just say dot play

perfect

cool so now let's hit run

and now we punch

all right there you go so now it works i

figured out i named i gave the wrong

audio files in here it was a dot wav

file so i changed it to mp3 so if you

fork this rebel at the time watching

this video it should say mp3 and it

should be good to go like you don't do

anything different code wise so let's

test it out hit run

hey there you go a nice crisp punching

sound i'm like literally punching myself

and that's the funny part about this so

cause he's punching lance doing random

damage

nice

so the cue button works all right

the next thing you want to do is set up

the e button

right

same conditions

but this time it's for heal right this

should say

then heal

perfect okay

so after that's done you set up the same

condition if

e dot key is equal to where do we want

to make the heal button to for player

one

it's gonna be a right you could set this

to whatever you want right the cool

thing i love about this is that you can

add this to your own game your own

project right so if you understand this

we can reuse those pieces again and

again so a

and right b

one right well p2 we could also put

p2.health here

mostly because if i'm kazi and my health

is zero he shouldn't be healing while

i'm dead right we should just not be

able to play so p2.health is greater

than zero

then p

and

right

and game dot is over is equal equal to

false right then we shouldn't be able to

heal

all right actually

no no no if it is true then we should be

able to heal yeah yeah there you go

so after healing play the heel sound so

let's heal so to heal you guys want to

do this p1.heal parentheses p1

and then we could say

something like

uh document

element

by id

and i will save you guys to look it's

just going to be p1 here

save you guys some time there and how do

i play the sound at that dom element

it's going to be play so run

hit attack

that's it heal

oh

it's not playing

you need to double check

run

oh now it's not loading

okay let me try refreshing

oh i don't want to lose this progress

okay

let's check our progress

ah there it is we lost it

so let's put this back on here

the sounds are correct yep yeah see how

it says mp3 now before if you looked at

the video it says

wav it should be mp3

there we go

so if i press q

p one attack play

what the hell

okay i see what's wrong this if

statement

needs his curly brackets

okay cool so now we can bring this back

uh we can bring back this sound

okay cool so the strike is the same

the heel is what's new i took out the is

over false right that should actually be

covered over here

let's hit run and now it was a q

okay it shouldn't be playing that heel

sound

okay

how about heal

all right heel's working fine

now it's this guy why are you playing

both sounds

and healing

let's see

ah

okay i see now all right so you tell me

guys if you see the error and the error

is actually in the heel

all right

what is the difference between one equal

side and two equals sign so i totally

forgot this should have two otherwise

it's recognizing every key as the the

key press for heal all right even if i

press q

so there you go that's kazi punching

now he heals

perfect

right so now it's starting to get fun

right well fun for qazi not really for

me because i'm getting beat up here

all right so let's add my controls and

guess what the controls is the same

exact thing so let's do the if statement

all right if e dot key is equal equal i

won't forget this time

and the punch for lance or me is going

to be p

and we do the and

i want to make sure if kazi's health is

greater than zero i should still be able

to punch him right

and then and

uh game dot

is over is equal equal to false perfect

now after striking then play the attack

sound so let's strike

p2 dot strike

what is the arguments that strike takes

it's going to take in the player and i

love that replit shows you you know like

the little comments of what arguments

does it take takes in the player the

enemy and the damage so the enemy is

player one or kazi and the attack damage

is my

attack damage

and it's like that okay

and after we strike we need to play the

sound and to save you guys some time

it's basically

document

dot get element dot get

element by

id

and i believe it's p2 attack right i

have to make sure you can just look over

here it is p2 attack

that's how you get that id then you hit

play

okay cool

let's hit run and hp

oh

i attacked myself

uh

that's not good

there you go for some reason when i the

names were switched around and that was

really confusing so i hit refresh

and now let's see if cube

okay that works fine

if e dot key

oh can't forget the curly brackets

okay

i hear two sounds

there you go that's one now i'm going to

punch quasi

[Music]

and they switch places

that's interesting

oh that's a really funny bug it's like i

punch

and then they switch

oh and i think it's because of the

strike

okay

so going back to the top guys

let's go to the strike

and where it says update game this is

going to be different so this is too

dynamic so we have to put back this to

player one and player two and i actually

had that before

so now

we're not gonna get that weird switching

names i'm when i put player and enemy

there i'm saying that they're switching

roles so that's why you see kazia lance

switch and now that's why i got confused

but now

there we go

all right now we can actually fight the

game i can heal

well kazuki can you actually can't heal

yet

now there's like a back and forth here

it's making it a lot more fun

there you go so that cleared it up just

to recap make sure in your strike

function when you update the game it

shouldn't say

player enemy

it just should say p1 p2 so go to line

79

change this from player to p1 change

this from p2 to enemy because it should

be the same it shouldn't be able to be

switched around

like that shouldn't be dynamic

in this sense

so cool that's strike

so now let's do the if statement for the

heal which is pretty simple the key is

going to be

l

for here

right not capital l lower case and if

you know p1 that health is greater than

zero

then we should be able to heal still

and i can't forget the curly brackets

so inside the curly brackets

it says after healing

play heal sound

so let's how do we heal as player two

just use the method and pass it in

then how do we play the sound we get the

dom element

which should just be

p2

heal

and then do dot

play

awesome

and that should be it so let's hit run

and let's see if we have a game

oh i love the heel sound effect for my

my heel it's like whoop

whoop and then kazi says

[Music]

right

and

hey

lance wins did you hear that

that is the victory sound from declare

winner

let's see well i passed it declare

winner

drink the man right here play the

victory sound

right now the only problem is after we

play the game

it's like a one-time use we can't play

anymore because this reset button

doesn't work

so

we're almost done guys we just need to

set up this reset button

right and the reset button is pretty

simple we just kind of set all the

values back to its original state right

so what i mean by values i mean p1

health causes health and my health

sending it back to 100.

so all you have to do is just say

p1 do i have access to p1 yes i do

i say health

is equal to oops 100

all right p2.health is equal to 100

right and then we also want to set the

game is over to what do you want is over

to be false again or true again

false because

if this dot is over

is equal to

false that means we can keep playing

and

do we want to see lance wins right i

don't think kazi wants to see my name

and for resetting right my name winning

and for resetting so we're going to get

that result div again

get the inner text

and how do we make it so that it doesn't

show lance wins well we can just say

empty quotes that's going to make it

blank that's how you clear your inputs

that's how you clear your dips

and

when we're set we should also

update the game

to p1

p2

and

set the game state to whatever this dot

is over is perfect so if i hit run here

let's uh play the game

[Music]

qazi wins let's hit reset

ay and then we can just play again

let's see who wins this time

i win this time right this is getting

this is really fun i had a lot of fun

making this guys with that said that's

pretty much the fighting game app right

so it wasn't too bad it looks like a lot

of code but if you really break it down

it's just understanding each piece like

all right you want to reset just get the

player health all right what do you want

to set the health to 100 all right how

do you make sure the game is playable

false

right so if it helps to write stuff down

and look it over again feel free to do

so right the last function here is the

play button this is going to be the

bonus feature it's the simulation right

if i hit reset i should be able to

simulate the game and just see what

would happen right

so to play

i usually like to reset to make sure the

player's health is back to full before

starting right

so how do we reset the game

well reset is a method within game so if

it's within game and you're calling

something within itself you can say this

right this represent rob is pointing to

itself

so that just means the game it's like

saying game dot reset

right game.reset takes two parameters p1

and p2

right

and that's it

okay cool

now we have the while loop so we went

over while loops in that prep video that

i had with you guys

that prep video that i have with you

guys and what we want to do is make sure

both players get to strike so that means

kazi goes once and then heals and then i

go once heals and then it just keeps

looping till this

dot is over

is

true because the second this turns true

the match is over

right so

all you have to do is just call the each

command right that's it so that's just

p1 dot strike

p1 p2 and p1 dot attack damage that's it

so kazi got to strike in the simulation

now what we should do next is p2.heal

right this could be any order that you

want so now kazi strikes i heal right

this is kind of the script

so in this script i heal and then now i

strike

so it's going to say p2 is the player

the enemy is p1 and we're going to take

in my

attack damage

okay cool

[Music]

right

and then there's also

p1 dot heal

all right p1 so i so this is the script

guys cause he strikes i heal i strike

cause heals all right cause he strikes i

heal i strike i was going to keep doing

that to one of us dies which will happen

eventually and this is the way to make

it most fair right in a while loop so i

don't have to do any work at all

right so once is over is true which

means we're out of the while loop

right we're going to declare the winner

so we can just say return

this dot declare winner

and we can say

this dot is over

p1 and p2 right because remember declare

winner

takes in the game state

p1 p2

perfect

cool and then

uh there is a glitch where it says

undefined so let's just make the message

say tie right it's a tie

when i can't determine who wins

okay

cool

so now that we have that functionality

just double check everything

time test it out

now to actually run the code

i had a little to do here which is add a

click listener to the play button right

so

we need to find the div that holds the

simulate button so if you look at the

top here

going up the top there is a

play button right here play button right

that's going to hold play so all you

need to do

[Music]

is come down below here

and say play

button dot on

click

all right it's lowercase because it's

not react

is equal to the function where

result

dot inner text

is equal to

game dot play and then you put in

p1

p2

perfect

let's hit run

okay so now that you have that we can

hit the simulate button it should work

now let's go lance wins right

how's the tie

kazi wins there we go cool so now the

simulate button works and we're free to

just simulate or we could reset and we

could just start playing

and you can make this fighting game even

more advanced you can add like a kick

option that does more damage you can add

like a i don't know a special move like

hadouken and it does even more damage

right all you have to do is go to the

player class

right and add that method in here right

this is what you need the essential

tools to create something like this and

i hope you guys enjoyed if you made it

this far in the video congratulations

this is the fighting game

so

sami show me how i did share with us how

you did the fighting game and make sure

to fork this ripple and place it back

into the main course so let me show you

guys how to do that

okay so let's say your code is working

and it's up to date all you guys need to

do is go to the main replit again

right

and you can go to the solution and

compare it to how i did in the solution

and what you could do is put your code

in the exercise folder so if this is

your index right you want to take

your index

click ctrl a

ctrl c

and then paste it on here

right so that it's up to date and has

your code

okay

so once you do that your reply is

complete right we moved over here so you

could test stuff a lot easier

perfect so that's it that's the fighting

game guys i'm glad you guys walked

through it with me

thanks for watching this part

all right so you've made it to the

netflix clone i'm excited about this one

because there's a little bit of a story

that goes along with this so let's let's

think about a scenario right netflix is

hiring you as a developer to fix their

app alright if you click on this button

right here open in a new tab

you're gonna see that looks pretty empty

that's because the movies aren't being

loaded in properly so it's your job as a

developer to make the api call and pull

the movies that we need it should look

something like this so if you go to your

javascript course rebel go to open

in the new tab for that you should see

this nice page create netflix and bam

this is what netflix is supposed to use

and this is what netflix is supposed to

look like and as you can see all the

netflix originals are here stranger

things season four if you guys are

watching let me know how you guys think

about it and then there's trending now

and there's also top rated movies right

so if you didn't know in the background

this is using an api from moviesdb so

we're going to be working with a real

api and if you get it working netflix is

up and running again so this is what it

looks like what you're going to need to

do

is hex to exit this out hop over back

into the exercise folder and take these

files you're going to notice a link to

this

replicate netflix project and this is

where we're going to be doing most of

our coding

so let's get started and let's take a

look at the assignment so here's our app

make netflix

here's the scenario where we have to

make sure that fetch movies is working

so the core functionality of this app is

to get fetch movies working

right and fetch movies is going to take

in a url

a div id

or a class

right so fetch movies is over here as

you can see the api url the dom element

right what do i mean by dom element what

do you guys think what is a dom element

right so with dom element it's going to

be one of these it's going to be either

original movies which is a class

trending or top rated right why would i

want to put

dom element as an argument

right because

this is actually

a dynamic

function right why is it dynamic if you

remember what dynamic is it can be

inputted with any

you know parameter or argument and still

get you the right itself right result

it's not hard-coded right so

later on i need to make an api call a

separate one to get the trending one but

where do i want to put it well that's

where dom element comes in

dom element is just who doesn't

represent one of these guys right so if

i want to put it in trending

right

i need

this dom element the trending div

because that's where i want to put it

and then if you notice there's something

called path type

that one you might not know but when you

look at the data there's two types in

here there is let me see let's bring

back let's bring that back in here

[Music]

there's two types of paths what i mean

by paths is this if i could create

netflix do you notice the difference

between these movies and these movies

well this is called poster path and this

is called backdrop path it's the wide

one so you have to define

on your api data which path is going to

do you want a posterior path or a

backdrop path all right that's what

that's here for

cool so that's what path type is and

again here we're going to use the fetch

method right to call the api

and then we're going to use fetch to get

the response

and then call something called show

movies that's another function

right so this is a function

that displays the movies to the dom

right so

fetch movies is just fetching the movies

show movies is another function that's

gonna show the movies over here right so

we're gonna need to take that object and

place it into the down all right nothing

new right i'll walk you guys through

that eventually but i think you guys

know how that's done right

next we have a function that fetches

netflix originals right so these three

functions are gonna need some api calls

so what i did is x tap the tab over here

and let me get you the api

that you're gonna need so the url for

this one all right let's do a comment

here

a url to get originals is going to be

this api

and the cool part is you don't have to

worry about getting an api key i already

got it for you it's this one right here

all right then we can also

get the url for

sorry this is the url for trending

we need a url

[Music]

for

original movies

which is just going to be this

yep and then we can do something like

this oops

like that

and see the top rated url i have for you

guys it's going to be

right

url

pull in and boom there you go

so these are the urls that you want to

use and you're going to use these and

put them into fetch movies right so

after you get the url

you're gonna call

call fetch

movies

all right so as you can see fetch movies

is the key here so i'll put this three

times so after this

call fetch movies and after this

call pledge movies

all right why am i calling fetch movies

because fetch movies again is already

making the api call right it's already

making an api call i'm taking a dynamic

one and then you're gonna choose where

it goes right so it's already being

handled right it's a helper function

right it's called a helper function

because it's helping get originals fetch

the movies it's helping trending fetch

the trending movies right or using it

dynamically alright so that's pretty

much it for the app what you need to do

is figure out how it comes together and

i would start with

this function on line 45 okay so best of

luck this is definitely a little bit

less complex than the fighting game that

you guys have done but i think you guys

can do it and if you get this working

you're free to do whatever you want with

this ui because you can use this to make

your own netflix change out the code to

make i don't know disney plus

however you guys want to move it

however you guys want to do it so

good luck i'll see you guys in the

solution

awesome so how'd you guys do were you

able to get it working if you were close

or you got to finish congratulations you

have netflix right if you didn't this is

what the solution part is for and maybe

you can see maybe that i coded it a

little bit differently or maybe you

coded it better than me right hats off

to you if you did but let's walk through

the solution right so we have the make

netflix app we have fetch movies and the

three main functions and i just realized

the url is already on here so i didn't

need to paste it down below that's okay

we'll keep it moving we're gonna see the

great originals trending now top rated

right so let's break this down

here are the divs that we need to know

original movies has the netflix

originals trending has trending yada

yada you guys know that right here's an

interesting one window

dot unload

right

it's exactly what it sounds like it's

basically a method right because it's

coming from window

and when the window loads

run these three functions so

it's going to run those three functions

and then display it on our netflix app

right but at the moment you're not going

to see anything

right because

those functions don't exist or they

don't do anything right they're blank

all right so let's start with the core

of our functionality and that's going to

be on fetch movies so let's hop over to

fetch movies that's gonna be on line 45

i believe yep it's right there

so now that you're on fetch movies

we're gonna need to do is take a look at

url dom element and path type i

explained this in the last video so to

get started using it you just want to

say fetch right

and then how do i fetch

you know api data

well you just put the api url right so

that could look two ways it could look

like this

fetch this whole thing

or

and this would work you could totally do

this but this is only getting top rated

as you can see

but i want to make fetch movies dynamic

so how do i make this dynamic

just type in url

how come that's allowed well i'm passing

that as an argument right i'll put that

long string when i call the function

later cool so after that we can do a dot

then all right and again with the cool

thing with that then is you can just

write it like here

parentheses and

remember dot then is handling what you

want to do

after the promise is resolved right so

if i say uh that then here and i say

response

and then say arrow and then say

console.log

response

okay cool so if i hit run here boom

nothing really happens and you can even

check it on inspect element over here

nothing all right reason being we didn't

really call fetch movie so let's do that

right here

all right so coming down below here

we're just going to call fetch movies to

test it out and

here we need to pass in a url dom

element and a path type

but are we using dom element or path

type just yet nah we're not using it

just yet so we're gonna just pass in a

url and i can't just write url here

because then it'll be undefined fetching

undefined right so let's pass in a real

api url which was this one up the top

get originals

and we'll paste it right here and let's

put some more space so you guys don't

get confused all right this is a

function call

passing an api url we can also hit

refresh here

because it's going to run

then console and look at that response

right look at this we got a response

here's everything we need the headers

the status status 200 means it's good

which means we're good to go right so

now that we have the response though

we need to do something else

and something else with the response

right

well in here

if

dot okay

right if it's successful or if we got

200 we're gonna return

right

response

dot json right

cool

then we can add an else

all right and then we can just throw

an error so we can say throw a new

instance of an error right the classes

are coming back here right something

went wrong just in case something went

wrong along the way we can have this

else statement

cool but

as you see we got the response object

but we didn't get any data right and the

okay is true so that's good

we didn't get any data all right what we

need to get the data is go over to line

54

where this parentheses and you're just

gonna have to type in dot then remember

dot then is handling what we get back

from this right

so

basically after that then and you can

change multiple dot then you can do that

then that then not then this is the

second dot then

and this parameter we'll call data

right and then we will console.log the

data right

so there we go let's hit refresh

and look when i contact data this is

what we get back we get an object right

most of the time when you make an api

call you're going to get an array of

objects

or just an object itself so this time we

got one object right and if we open it

up we got results which is what

right an array

right and inside that array what's

inside that array let's open it up

objects

right and notice something

there is a backdrop path

the back drop path is a character is a

what's it called a property

with a value

of the image remember backdrop is the

wide one right so let's open up zero

again

so there is the backdrop path and here

we have the poster path right so i

didn't just make this up this is how we

can determine whether we want the path

type to be the backdrop or the path type

to be the poster right so there's fetch

movies and now it's pretty much set up

right the only thing that we could add

here is a dot catch all right.catch is

just here because if there's any error

we can say error

and then arrow here and say console.log

error

right

okay cool we're actually pretty much

done with the fetch movies already we're

fetching the data right

but then we want to take this whole data

and show it onto our app

right so how do we show movies right

luckily we have a function for that show

movies all right so what i'm going to do

is i'm going to erase this because we

don't want to call fetch movies here all

right we're going to call it somewhere

else what we want to care about now is

show movies right

show movies

is exactly what it sounds like and its

job is to display that movies

that object that we got back all right

this thing

this results

array

and display it like all of these 20 and

display it into our dom over here right

so that means we're going to use the dom

and how do we select things from the dom

all right

so one of the very first things that

we're going to do is create a variable

that grabs the id or class

right why do i say or class right

that's because

we have a class that's going to hold

original movies and the rest are ids

right

so

what we're going to do is make a

variable var

movies

right

element right because it's a dom element

is equal to

so if i wanted to get a class or an id

right i'm not sure what it is

can i use document.getelementbyid

not get element by id right this is only

going to grab an id it's not going to

get a class

how about

by class name right this could work too

but that's only going to be class

so what i want to do is grab query

selector document.we're

right

document.queryselector if you don't know

it's just going to grab

the first instance of the class or id

right what do i mean

let's say we have four boxes right and

they're all classes called box it's

gonna grab the first box if you have

four ids it's gonna grab the four id

luckily

right we only have one of these one of

these one of these so

it's always gonna pick the right one

so query selector and how do i make it

so it's dynamic right i want to grab the

trending one so i could just write you

know trending here

and it would only grab trending right

it's static but to make it dynamic right

we have access to

dom underscore element

and where does dom element come from it

comes from this argument here and that's

what we're passing in

okay cool

next thing all right we're going to loop

through

movies object

so

remember the part on the javascript

course about objects there's a way to

loop through them and you can use

something called the four of loop right

so to use a four of loop you say four

just like we do with a for loop right

but to use four of you're just gonna say

four

let

movie

of the object name so what is the object

name here

right

it's going to be called movies right

but let's think about this

what am i looping through if i just say

movies

if i'm looking through movies i'm

looping through this whole object

right but where in this object does the

movies live

it lives in the results

right so i want to be looping through

the array

right of objects so

how can i if this is if movies is an

object how do i get the results from

that object

aha

right you guys got it results

so let movie of movies dot results okay

so from here we can console.log

right

uh movie let's start let's stop there

just to make sense of it all right

and instead of console logging the data

in line 55 i don't want to print it i

want to call show

movies right

and for now we're going to say url right

that's what we need to pass here url

actually not url we should pass data

because that's the object right the data

is the movies

the dom element right we can keep that

the same and the path type we keep that

the same

cool

so to get this up and running right show

movies is gonna get called when i call

fetch movies so what we should do is

call fetch movies let's call fetch

movies again

test it out see if i have it pasted

right nice i still have the api

right then we're going to say the dom

element is the original and the original

is like this

all right original movies

yep okay so original movie just copy

that that's the class name comma

and it should be dot original movie

since it's a class

and in the comma we want

poster path poster underscore path

all right so let's hit

refresh on this

and you see this console log where is

this console coming from it's coming

from

this in line 70. so we're consolidating

what a movie is

so what is a movie then what does this

tell you

right

it tells me

that these are all the objects

inside of the movies array all right if

our console log

up top here console.log

movies.results right

let's hit refresh on this

at the top here see this array of 20.

that is movies.results

we're we're looping through

movies.results so movie

is each individual object so this is the

first one which is stranger things this

was all of us are dead lucifer squid

game first kill right it's exactly what

it sounds like every movie

in movie results

okay so when i say movie i'm talking

about each movie cool

so what do we want to do with this loop

then all right what do we want to do

with each movie

well

with each movie

right

i want to create an image element right

there should be an image element if you

remember the finished app

right

let's uh bring it back again and keep

bringing it back i should just keep it

let's go here

open here

and let's look

oop

let's look at create netflix

each of these is an image tag with the

data of that movie right so what we need

to do is for every movie and movie

result let's create an image element

right so we can actually create that by

making a variable so we can say i've

been saying var let's just say let to

keep it consistent let

and let so let's say let image element

right

and set this equal to document

dot

create

element all right this is how you create

an element using the dom

img this is making an image tag right so

this is this comment right here

within loop create image element

all right let's get these also in here

[Music]

set attribute

set source i can actually copy all these

awesome all right so now we need to set

an attribute right

so the attribute of this

is going to be

image

element right that's the variable

holding the element and we're gonna make

an image tag for every single movie

all right

image element dot set attribute right

is data

dash id

and then you're going to comma

movie right what's movie

movie is the object all right and how do

i get the id

right right here id

so how do i get an id of the movie

object you say movie.id

i'm saying attribute as data id okay

cool so now when you see set source here

that is the actual image itself right

this is creating the image tag this is

giving it an attribute of the id this is

putting the picture in the element make

sense

cool

so we can do an image element dot source

right that's how you change it it's

equal to

and then we have to have the link

so the api link for this is universal

right

it's going to be something like this

boom

image

element.source is equal to

this

image path right where am i getting this

from well if you look

that is the url of the image and over

here it just needs the path to add on to

it

right so we put this

after

original

then you get the backdrop but if you put

oops if you put

this poster path in front of the url you

get the poster

that's how this works

right but now what is this what is this

uh

dollar sign template movie bracket path

type

well

this is going to get you

it's a dynamic way to go into the movie

object

and

path type remember it's dynamic it could

be backdrop or poster

if this says if this were to say

something like um

back

drop

path then it's going to get only the

backdrops it's static if i said poster

path it's only going to get the posters

but if i say

path type

path type then it's going to get

whatever i passed in so now it's dynamic

cool

oh i copied it over

there we go

now i can go back like so perfect

so the next thing we need to do is

uh we actually don't need to add these

an event listener i'm gonna take that

out but we can add this

append the image element to the dom

element selected right what does that

mean right what it means is let's say i

want to add original movies or that's

what this data is it should go

underneath netflix originals right so

how do i put those image tags right

that's the step we

fetched the data

we

got each individual movie

we created an image tag we put the

picture in there

where do we put them that's what the

step is where do we put those images

right and where we put them is going to

depend on what we put as the dom element

so if you look under

the original movies

this is what we need we need to put it

in this div right so how do we put stuff

in this div

well we're going to use the append

method

right

so let's come down below right here

and we can say movies

element

right dot append

child right so child right is whatever's

inside the div right so

basically

add

image element

to the movie element right so now we're

combining it together so l

element

oh element there you go so now we

appended the child to the dom element

selected

yep so we're selecting the dom with dom

element and it's movies l and when we

say movies l add an image element to

that movies right so what is that

happening visually basically add

stranger things to that div add this

movie to that div add lucifer to that

div it's going to do this one by one

because of the loop

for every movie in movie result create

an image tag set the attribute put the

source in and add it to the div and then

again create the image tag create the

source add it to the div until

all 20 is done

makes sense and that's guess what that's

it that's show movies so if i were to

let's hit refresh

on this guy

see what happens

hey look at that exactly how i said it

it appended

a movie element

onto netflix original so the first part

is done right

that's sick right but now it's gonna go

away because i'm gonna erase fetch

movies right because this is a static

way of doing that like the point of this

exercise is to show you dynamic api

calls right so i erased it and now if i

refresh

we lost the progress but you guys know

how it works now right

so with that said

right

show movies is done fetch movies is done

now let's make the dynamic calls right

notice how i have the api already for

you what you need to do is just say let

url

right

let url equal to this

right and then we call fetch movies

remember the thing that we just erased

right now we can add it back in but this

is forget originals so

d you could type in this whole string

here but it would look very long

right

you could

just type in url

why that's because we have url right

here all right holding this long string

that's another way another trick for you

guys if you have a really long api call

and you don't want to you know fill up

your function calls with that long

string you can just store it in a

shorter variable all right making use of

variables here

and then

put the same exact parameters dot

original underscore underscore movies

comma

poster

oops

the poster path

awesome so this is get originals and if

i were to hit refresh on here

it works again right it works again

because

why why is this working even though i

didn't call get originals well if you go

at the top remember that windows unload

it's already calling it

right so we are one third of the way

there the rest is simple

so call movies

let's figure out that so we can just

call fetch movies here

we can take this comment that i made for

you guys and do

let

url equal to

this right

and pretty much do the same thing

i can say url

and this time right it's different we

want to say

hashtag trending why are we saying

hashtag trending

it's hashtag because this is an id you

got it

so trending

and we want the

backdrop right the wide one backdrop

okay

i love coding because once you know the

individual piece

it starts to get a lot simpler because

it's the same pattern over and over

again okay so now that that's done if i

hit refresh here

hey trending is available

awesome

okay top rated same deal let's hit let

url equal boom

call fetch movies

right we can say url here

comma

the next thing is going to be top rated

and is that a class or an id

it is

an id top rated

all right so this isn't too bad right

guys if i do back drop underscore path

hit run

right at refresh

let's frickin go and with that said guys

this is your netflix app where you can

go big and small

look at that

awesome so look at that you made netflix

you've got it working your boss is happy

right feel free to take this project and

do whatever you want with it right you

can make your own netflix you can make

disney plus

right but this is how it works you guys

learn how to make apis and they're

dynamic so congratulations this is it

for the project

give yourself a round of applause and

this has been awesome

wow that was a lot i mean that was over

10 hours of content if you got to hear

start to finish first of all i love you

my adsense loves you thank you so much

and i think your skills javascript

skills went

way higher now you're still not a pro

but this is way more than you might have

ever done okay and you definitely have

increased your skill set so give

yourself a huge pat on the back i'm

really proud of you for getting to here

i hope this was exciting riveting fun

engaging insightful interesting and more

than anything else just curiosity

inducing i hope that you want to

endeavor on this journey and on this

path to like learn more javascript and

just improve your coding skills i had a

lot of fun making this for you our team

had clever programmer me and lance david

everybody had so much fun putting this

course together for you i hope you

enjoyed it but let this be just a start

in your journey there's so much more for

you to do i can't wait to see what types

of projects you build because that's

what you need to do now okay it's all

about building projects with this and

taking this to a whole another level so

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so thanks so much for watching and as

always this is qazi and i'll see you in

the next video