Node.js Basics

JavaScript on the Server

Node.js is a JavaScript runtime built on Chrome's V8 engine, enabling JavaScript to run outside the browser for server-side development.

Core Concepts

• Event Loop: Non-blocking I/O that handles concurrent operations efficiently
• Modules: CommonJS (require) and ES Modules (import/export)
• npm: Package manager with the largest ecosystem of open source libraries
• package.json: Project manifest defining dependencies and scripts

Async Patterns

• Callbacks: Traditional async pattern (callback hell)
• Promises: Chainable async operations
• async/await: Synchronous-looking async code

// Reading a file asynchronously
const fs = require('fs/promises');

async function readConfig() {
  const data = await fs.readFile('config.json', 'utf-8');
  return JSON.parse(data);
}

Built-in Modules

• fs - File system operations
• path - Path manipulation
• http - HTTP server and client
• crypto - Cryptographic functions
• events - Event emitter pattern