All language subtitles for 2 - What is the MERN Stack English

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.