Node.js Tutorial

Simply put, Node.js is JavaScript that runs on the server.

Node.js is a platform built on Chrome’s JavaScript runtime.

Node.js is an event-driven I/O server-side JavaScript environment based on Google’s V8 engine. V8 executes JavaScript very quickly and performs well.

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Who is this tutorial for?

If you are a frontend developer who does not know dynamic languages such as PHP, Python, or Ruby, and you want to build your own services, Node.js is a great choice.

Node.js is server-side JavaScript — if you already know JavaScript, you can learn Node.js quickly.

If you are a backend developer and want to deploy high-performance services, learning Node.js is also a strong option.

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Prerequisites

Before you continue, you should know some basic programming concepts. Experience with JavaScript, PHP, Java, or similar languages will help you pick up Node.js faster.

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Version used

You can check your current Node version with:

$ node -v
v4.4.3

TIP

Behavior can differ across versions.

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First Node.js program: Hello World!

Script mode

Here is our first Node.js program:

console.log("Hello World");

Save the file as helloworld.js and run it with the node command:

node helloworld.js

When the program runs successfully, the terminal prints Hello World.

Interactive mode

Open a terminal, type node to enter the interactive REPL, then enter a statement to run it immediately, for example:

$ node
> console.log('Hello World!');
Hello World!

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GIF walkthrough

The following GIF demonstrates the steps:

Next: Node.js Installation