Introduction to Node.js

Node.js is a JavaScript runtime built on Chrome’s V8 JavaScript engine. It allows you to run JavaScript on the server side.

What is Node.js?

Node.js is designed to build scalable network applications. It uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

Why Node.js?

JavaScript everywhere: Use the same language for frontend and backend
Non-blocking I/O: Handle thousands of concurrent connections
Large ecosystem: npm has millions of packages
Active community: Regular updates and improvements

Getting Started

Check if Node.js is installed:

bash

node --version
npm --version

Your First Server

javascript

const http = require('http')

const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' })
  res.end('Hello, Node.js!')
})

server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/')
})

ES Modules

javascript

// package.json: "type": "module"
import http from 'http'

const server = http.createServer((req, res) => {
  res.end('Hello with ES Modules!')
})