Original subtitles

‫So what's MERN, what does MERN stand for?

‫The M stands for MongoDB and that is a database solution,

‫the E stands for Express,

‫I'll come back to what this is

‫in a second.

‫The R stands for React.js

‫and this is a browser side Javascript library that helps us build amazing user interfaces and the

‫N stands for Node.js,

‫this is a server side Javascript runtime, an environment where Javascript code can be executed outside

‫of the browser and now Express.js is a framework for Node.js,

‫so it in the end makes building Node.js applications easier. Now combined,

‫these technologies form the so-called MERN stack.

‫They work together particularly well and you can build amazing full stack web applications with these

‫four technologies working together.

‫So let's take a closer look at each of these technologies to understand which role it plays exactly

‫in that tech stack.

‫So what's React? React is a client side,

‫so on the browser, library which allows you to build highly reactive user interfaces,

‫so it's all about building user interfaces. With React

‫you write Javascript code that will be executed in the browser and since it runs there, it is responsible

‫for controlling what the user sees on the screen and how things there change when a button is clicked,

‫when something is entered into an input box,

‫it's really all about that,

‫it's about rendering a user interface with dynamic data and about updating it when data changes or when

‫certain events occur.

‫It's about handling user input and providing feedback to the user

‫and it's also and that is where the other three technologies will come into play,

‫it's also about communicating with backend services and with backend, I mean services or technologies

‫that don't run in the browser of your user,

‫so React so to say is the front end,

‫the other three technologies - Node, Express and MongoDB together make up the backend.

‫Now we use libraries like React and there are alternatives like Angular with which you would have the

‫MEAN stack instead of the MERN stack which do the same

‫but we use such technologies to provide users with a mobile app-like user experience where everything

‫happens instantly, where we have a great reactivity, where things on the user interface really feel great

‫and in standard, we simply provide a really awesome and amazing user experience.

‫Now what about the other technologies, what is Node exactly?

‫It's a Javascript runtime typically used or often used to create server side Javascript applications.

‫Now technically, that's not the only thing you can use it for but it is one of the most prominent use

‫cases and scenarios. You can use Node.js to execute Javascript outside of the browser

‫And since it runs outside of the browser, you can for example use it to create a web server with it,

‫so to run it on some machine which is exposed to the Internet which then accepts requests and sends

‫back responses, so we can then use Javascript as a server side programming language, as an alternative

‫to PHP, ASP.net, Java and so on basically. With Node.js we can listen to requests and send back

‫responses,

‫we can execute server side logic and we can also interact with databases and with files, things we typically

‫don't do in the browser or we can't do in the browser, since we're not tied to the browser anymore,

‫there are certain things we can't do anymore,

‫for example interact with the DOM, because there is no DOM, it's running outside of the browser but there

‫are new things we can do, for example

‫write files or do things like this and therefore as I said, it's an alternative to other server side programming

‫languages and just like those languages,

‫it's also important to note that it's rarely used stand alone,

‫instead typically we use it combined with Express and Express is a Node.js framework, so we still write

‫Node.js Javascript code but we get utility functions and a certain way of structuring and building

‫our applications, so a certain ruleset we adhere to basically which makes building Node.js applications

‫much much easier.

‫So it's based on Node.js but gives us new functionalities,

‫it's strictly middleware based and you will learn what that means throughout the course,

‫which means we have a clear way of handling requests, a clear funnel through which all requests are passed

‫where we then can extract data or prepare the response

‫and in general, with other features like routing, view rendering and more, we've got a lot of tools and clear

‫rules that almost force us to write amazing and really well working Node.js applications.

‫So it really simplifies the usage of Node.js

‫and if you know PHP, it's a bit like what Laravel is for PHP,

‫an amazing framework that simplifies the usage of the language

‫and that leaves us with MongoDB, what is MongoDB about? MongoDB is a NoSQL database engine,

‫which allows us to store documents in so-called collections, instead of records and tables as we would

‫have it in SQL.

‫So it's a database engine,

‫it's all about storing data,

‫it's about storing our application data

‫specifically. We use MongoDB in this course

‫and in general to store for example our users, our products or whatever our application is about.

‫Unlike SQL, it doesn't enforce a schema for our data,

‫we can still build one and use one if we want to but we're not forced to

‫and we also don't need to work with relations.

‫We can still set up kind of relations but it's all a lot looser than it is in SQL,

‫you're not forced to do these things and this is the case on purpose of course because it also gives

‫you many advantages,

‫for example NoSQL databases like MongoDB often give you amazing performance because they're way

‫more flexible.

‫It's also very easy to connect it to Node and Express because as you will see throughout this course, writing

‫queries against MongoDB is really straightforward and super easy when working with Javascript anyways,

‫so it's really fun and easy to use MongoDB in Javascript applications. Now for security reasons, as you

‫will also learn throughout this course,

‫we don't connect to MongoDB directly from inside our React application,

‫instead we do that with the help of Node and Express and that is how we then have all these technologies

‫work together,

‫so it's a powerful database which can easily be integrated into a Node Express environment.

‫Technically however you could also swap MongoDB for other database engines,

‫it wouldn't be the MERN stack anymore because our M would be gone but of course you could also

‫you build an app with React, Node, Express and some other database

‫but as I said, MongoDB really works well and is super easy to use.