Path Module Essentials

The path module handles file paths. Essential for cross-platform code.

Why Use path?

```javascript // ❌ Hardcoded - breaks on Windows const file = '/users/data/' + 'file.txt';

// ✅ Cross-platform const file = path.join('/users/data', 'file.txt'); ```

Import

```javascript const path = require('path'); ```

path.join() - Combine Paths

```javascript path.join('folder', 'subfolder', 'file.txt'); // → 'folder/subfolder/file.txt' (Unix) // → 'folder\\subfolder\\file.txt' (Windows)

path.join(__dirname, 'data', 'config.json'); // → '/app/project/data/config.json' ```

path.resolve() - Absolute Path

```javascript path.resolve('file.txt'); // → '/current/working/directory/file.txt'

path.resolve('/foo', 'bar', 'baz'); // → '/foo/bar/baz'

path.resolve('foo', '/bar', 'baz'); // → '/bar/baz' (starts fresh from /bar) ```

path.basename() - File Name

```javascript path.basename('/path/to/file.txt'); // → 'file.txt'

path.basename('/path/to/file.txt', '.txt'); // → 'file' (without extension) ```

path.dirname() - Directory

```javascript path.dirname('/path/to/file.txt'); // → '/path/to' ```

path.extname() - Extension

```javascript path.extname('file.txt'); // → '.txt' path.extname('file.tar.gz'); // → '.gz' path.extname('file'); // → '' ```

path.parse() - Break Down Path

```javascript path.parse('/home/user/file.txt'); // { // root: '/', // dir: '/home/user', // base: 'file.txt', // ext: '.txt', // name: 'file' // } ```

path.format() - Build Path

```javascript path.format({ dir: '/home/user', name: 'file', ext: '.txt' }); // → '/home/user/file.txt' ```

__dirname and __filename

```javascript // Current file's directory console.log(__dirname); // '/app/project/src'

// Current file's full path console.log(__filename); // '/app/project/src/app.js'

// Common pattern const dataPath = path.join(__dirname, '..', 'data', 'config.json'); ```

Practical Example

```javascript const path = require('path'); const fs = require('fs').promises;

async function processFiles(directory) { const files = await fs.readdir(directory); for (const file of files) { const fullPath = path.join(directory, file); const ext = path.extname(file); if (ext === '.txt') { console.log(`Processing: ${path.basename(file)}`); // Process file... } } }

processFiles(path.join(__dirname, 'data')); ```

Key Takeaway

Always use `path.join()` to combine paths - never concatenate strings. Use `__dirname` for paths relative to your file. The path module ensures your code works on any operating system.