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Node.js

Overview​

Node.js is a JavaScript runtime built on Chrome’s V8 engine, designed for event-driven, non-blocking I/O. It powers CLIs, HTTP APIs, real-time servers, and build tooling (Webpack, Vite backends). npm is the default package ecosystem.

Key concepts​

  • Event loop — Single-threaded JS with libuv thread pool for I/O.
  • Modules — CommonJS (require) vs ESM (import) interoperability rules.
  • Streams — Handle large data incrementally.
  • Buffers & binary — Buffer, Uint8Array interop.
  • Security — Supply chain hygiene, npm audit, lockfiles.

HTTP request handling​

Sample: native HTTP server​

import http from 'node:http';

const server = http.createServer((req, res) => {
  if (req.url === '/api/health') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify({ ok: true }));
    return;
  }
  res.writeHead(404);
  res.end();
});

server.listen(3000);

References​