Jonas Notes

Node

1 min read

Node.js is an open-source, cross-platform JavaScript runtime environment that lets you run JavaScript code outside of a web browser. It’s built on Google’s V8 JavaScript engine and is commonly used for backend development.

Key points:

  • JavaScript beyond the browser → Lets developers use JS for server-side applications.
  • Event-driven, non-blocking I/O → Handles many concurrent connections efficiently without blocking execution, making it ideal for scalable network apps.
  • Single-threaded with libuv → Uses a single thread for event loop management, with a background thread pool for async operations (e.g., file system, network).
  • Package ecosystem → Comes bundled with npm, giving access to millions of open-source packages.
  • Cross-platform → Works on Windows, macOS, and Linux.

Common use cases:

  • Web servers and REST APIs
  • Real-time applications (e.g., chat apps, games)
  • Command-line tools
  • Microservices

Basic example:

// hello.js
const http = require('http');
 
http.createServer((req, res) => {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello, world!\n');
}).listen(3000);
 
console.log('Server running at http://localhost:3000/');

Run with:

node hello.js

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