The File System (fs) module in Node.js lets you interact with the file system — reading, writing, updating, deleting files and directories — all using JavaScript.

It comes built-in, so no need to install anything.

✅ Importing the fs Module

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const fs = require('fs/promises');

📖 Common File Operations

📄 1. Read a File (Async)

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fs.readFile('example.txt', 'utf8', (err, data) => {  if (err) throw err;  console.log(data);});

✍️ 2. Write to a File (Async - Overwrites)

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fs.writeFile('example.txt', 'Hello, World!', (err) => {  if (err) throw err;  console.log('File written!');});

➕ 3. Append to a File

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fs.appendFile('example.txt', '\nThis is appended text.', (err) => {  if (err) throw err;  console.log('Content appended!');});

❌ 4. Delete a File

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fs.unlink('example.txt', (err) => {  if (err) throw err;  console.log('File deleted!');});

📁 5. Create a Directory

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fs.mkdir('myFolder', (err) => {  if (err) throw err;  console.log('Directory created!');});

📂 6. Read a Directory

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fs.readdir('.', (err, files) => {  if (err) throw err;  console.log(files);});

🔄 Synchronous Versions

Every function also has a synchronous version with a Sync suffix:

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const data = fs.readFileSync('example.txt', 'utf8');console.log(data);

🚀 Promise-based Usage (fs/promises)

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const fs = require('fs/promises');async function run() {  try {    const data = await fs.readFile('example.txt', 'utf8');    console.log(data);  } catch (err) {    console.error(err);  }}run();