Node.js Introduction

Runtime environment, modules, npm, event loop, and building your first server.

Overview

Node.js is a JavaScript runtime built on Chrome's V8 engine that lets you run JavaScript on the server side.

Key Concepts

• V8 Engine — High-performance JavaScript engine from Chrome
• Event Loop — Non-blocking I/O model for handling concurrent operations
• npm — Node Package Manager for installing and managing packages
• Modules — CommonJS (require) and ES Modules (import/export)
• Global Objects — process, __dirname, __filename

Code Examples

// http-server.js
const http = require('http');

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

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

Practice

Install Node.js, create a simple HTTP server, and explore the npm ecosystem.