Node.js Cheat Sheet
# Node.js Cheat Sheet
## Modules
```javascript
import fs from 'fs/promises';
import path from 'path';
import { fileURLToPath } from 'url';
```
## File System
```javascript
const data = await fs.readFile('file.txt', 'utf8');
await fs.writeFile('file.txt', 'content');
await fs.mkdir('dir', { recursive: true });
await fs.rm('file.txt');
```
## HTTP Server
```javascript
import http from 'http';
const server = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'application/json' });
res.end(JSON.stringify({ ok: true }));
});
server.listen(3000);
```
## Express
```javascript
import express from 'express';
const app = express();
app.get('/api/users', (req, res) => res.json([]));
app.listen(3000);
```
## Child Process
```javascript
import { execSync, spawn } from 'child_process';
const output = execSync('ls -la').toString();
```
## Environment
```javascript
process.env.NODE_ENV
process.env.PORT || 3000
```
## Common Patterns
```javascript
// Read JSON
const config = JSON.parse(await fs.readFile('config.json', 'utf8'));
// Path joining
const filePath = path.join(process.cwd(), 'data', 'file.txt');
```