Introduction

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.

Think of it as running JavaScript in your terminal rather than in the browser.

Your First Node.js app

Go back to the root of your project, and create a backend folder. This is where we will put all of our backend code.

In here, create a file called index.mjs. This is the entry point of our application.

note

In this project, we'll use the .mjs extension for our JavaScript files. This is because we'll be using ES Modules, which is a new way of importing and exporting code. You can read more about it here.

In this file, add the following code:

console.log('Hello World!');

Now, in your terminal, run the following command:

node index.mjs

Using npm

Our application will use npm to manage our dependencies. npm is a package manager for JavaScript. It allows you to install and use third-party libraries in your application.

Initialize npm in your backend folder by running the following command:

npm init -y

This will create a package.json file in your backend folder. This file will contain information about your application, as well as the dependencies that your application uses.

Using modules

Node.js has a lot of built-in modules that you can use. For example, the fs module allows you to interact with the file system.

You can also import modules from third-party libraries. For example, the express module allows you to create a web server.