All language subtitles for 5. Understanding the Role & Usage of Node.js 55

So you hopefully got a first picture of what nodejs is and why you use it and what you use it for.

Now typically and also what we will do in this course, you use nodejs to run it on a server to write

server side code

and for that, we have to have a look at the full picture.

We have our users using a client computer with a browser, their mobile phone with a browser,

even mobile apps and we will come back to how nodejs can communicate with these later in the course

too

but for now let's stick to the traditional browser picture.

We get our users using the browser and there we can use html, css and javascript, javascript in the

browser to create webpages,

right. Now they visit a page, mypage.com and they send a request to do so,

for example by entering a url in the browser, a request is sent to that url.

Now there, this server comes into play.

We got our server, some computer running in the Internet which has the IP associated with that domain

which is automatically resolved for us

and on that server, we then want to execute some code that does something with the incoming request

and returns a response, often but not necessarily always as you will learn, this response is a html

page which the browser then in turn can display. By the way, it is not necessarily just html, it's also

things like css files or javascript files with javascript code for the browser, not for the server.

Now on the server, we typically do tasks that we can't or don't want to do from inside the browser for

performance or security reasons. We connect to databases for example to fetch and store data.

We do user authentication which we obviously can only do on a place the user can't access to make it

more secure and avoid it being hacked.

We do it for input validation to see if a user entered a correct e-mail address,

the browser can always be tricked,

users can even edit their browser side code.

You can open the developer tools and start working on that page you're on

but the server is of course sheltered from that,

the user can't access it.

And in general, we have our business logic on the server. Everything our user shouldn't see which takes

too much time to run in the browser,

where we obviously want to deliver a fast user experience or anything of that kind

and that is where we use nodejs.

So also javascript code

but this time, not on the browser but on the server

and this is where we use the many features

nodejs gives us and this is how we indirectly allow our users to work with the server through that request response

pattern, the direct access is not available.

So this is how we will use nodejs in this course also, we will use it to write code on the server

that returns data our users,

our clients can work with.

Now one important side note at this point of time, nodejs is not limited to running code on a server,

it's a javascript runtime and you even saw a first demo which did not do anything where we needed a

browser right,

we didn't spin up a server there,

we didn't do anything which we would have reached through a browser.

We'll do that a lot throughout the course but we haven't done it thus far because it's just a javascript runtime,

we can execute any javascript code with nodejs and often that is code that runs on a server and is

executed upon incoming requests

but you also often use nodejs for other code, for example for local utility scripts or build tools.

If you worked with let's say react or angular or vue or anything of that kind, you actually used nodejs

indirectly a lot for all the build processes

these languages or frameworks needed because nodejs is a great tool for writing utility

scripts.

You have access to the file system so you can write and read and manipulate files

and this allows you to do a lot of utility stuff on your computer that is never exposed to the public

and I just want you to know that

and I'll even have a section this course where I dive a little bit more in such build tools and non

server side language usages of nodejs.

In general and that is the most popular thing you do with nodejs though, you use it in the context

of web development and server side code.

So you use it to run a server

and actually and that is an important difference to PHP

for example, with nodejs you don't just write the code that is running on your server,

you also write the server yourself,

so the code that takes the incoming requests and routes them to your well other code. In PHP,

you have extra tools like apache or nginx which run the servers which listen to incoming requests and

then execute your php code, here

nodejs does both.

It does

that listening

and it then also does whatever you want to do in your code,

so that's important and that's something you'll see in action soon.

We also use it or we therefore also use it to run all our business logic,

so not just to listen to incoming requests but to then work with the requests data, work with files,

work with databases, all that fun stuff

nodejs is capable of and we'll do all that in this course obviously.

And we also handle the response side not just incoming requests, you will also learn how you use nodejs

to send back data to your clients,

be that html pages,

html pages with dynamic content or data only in the format of json or xml or even files.

So this is what we use nodejs and what we will dive heavily into in this course.

Alternatives to nodejs would be things like Python,

also with frameworks like flask or Django or PHP with frameworks like laravel maybe or standalone vanilla

PHP of course and more, asp.net, Ruby on Rails, all that stuff, these basically are all replacements

for

nodejs or nodejs can be a replacement for them and there is no clear winner.

All these languages are capable of doing the same kind of stuff

and of course they differ in some technical regards but in general, it's great to have that broad variety.

The huge advantage or one huge advantage of nodejs is that it uses Javascript, a language which you

need so much in modern web development

for all the frontend, for some build tools and if you then can also use it on the server side,

you don't need to learn a bunch of different languages,

you can use one and the same language and then use that for your server side code too.

This is why nodejs is a great language to learn,

you get so much efficiency out of it,

it's also a highly performant and popular language.

There are so many jobs out there for nodejs,

there never was a better time to learn it.

It's used in so many environments,

also for a lot of cutting edge stuff but in general, nodejs is a great solution,

it's trending,

it's fast, it's efficient and it makes sure that you only need to learn one language to write all the

code you need in a modern web application.