FS Module Asynchronous Methods

FS Module Asynchronous Methods — a practical guide to fs async Node.js with clear examples you can reuse in real projects.

FS Module Asynchronous Methods — 13/55 in the Node.js series. Full playlist companion: Node.js complete course on YouTube. Prefer one article? Read the complete Node.js tutorial.

Short description

Async fs methods accept a callback `(err, data)`. Errors come first — always check `err` before using the result.

Async FS with callback

const fs = require('fs');

fs.appendFile('log.txt', 'New linen', (err) => {
  if (err) return console.error(err);
  console.log('Appended');
});