Express.js Cheat Sheet

npm init -y
npm install express
 
# With TypeScript
npm install --save-dev typescript @types/node @types/express

app.get('/users', (req, res) => {});   // GET
app.post('/users', (req, res) => {});   // POST
app.put

// Single parameter
app.get('/users/:id', (req, res) => {
 const id = req.params.id;
 res.send(`User ${id}`);
});
 
// Multiple parameters

// /search?q=javascript&page=2
app.get('/search', (req, res) => {
 const { q, page = 1 } = req.query;
 res.json({ q, page });
});

// routes/users.js
const express = require('express');
const router = express.Router();
 
router.get('/', (req, res) => {});
router.

// Parse JSON body
app.use(express.json());
 
// Parse URL-encoded body
app.use(express.urlencoded({ extended: true }));
 
// Serve static files from 'public' directory
app.use(express.static('public'));
 
// Serve from specific path

// Application-level
app.use((req, res, next) => {
 console.log('Time:', Date.now());
 next();
});
 
// Route-level
const logger

npm install cors helmet morgan compression cookie-parser

const cors = require('cors');
const helmet = require('helmet');
const morgan = require('morgan');
const compression = require(

// 404 handler (after all routes)
app.use((req, res, next) => {
 res.status(404).json({ error: 'Not Found' });
});
 
// Error handler (4 parameters!)
app.use((

app.post('/api/users', (req, res) => {
 // Body data
 const { name, email } = req.body;
 
 // Route parameters
 const

app.get('/api/demo', (req, res) => {
 // Send string/HTML
 res.send('Hello');
 res.send(

const express = require('express');
const app = express();
app.use(express.json

npm install pg

const { Pool } = require('pg');
 
const pool = new Pool({
 user: 'postgres',
 host: 'localhost',
 database: 'mydb',
 password: 'password'

npm install @prisma/client
npx prisma init

const { PrismaClient } = require('@prisma/client');
const prisma = new PrismaClient();
 
app.get('/api/users', async (req, res) => {

npm install zod

const { z } = require('zod');
 
const userSchema = z.object({
 name: z.string().min(2),
 email: z.string().

npm install jsonwebtoken bcrypt

const jwt = require('jsonwebtoken');
const bcrypt = require('bcrypt');

npm install multer

const multer = require('multer');
 
const storage = multer.diskStorage({
 destination: (req, file, cb) 

npm install dotenv

PORT=3000
DATABASE_URL=postgresql://user:pass@localhost:5432/db
JWT_SECRET=your-secret-key
NODE_ENV=development

require('dotenv').config();
 
const PORT = process.env.PORT || 3000;
const DB_URL = process.env.DATABASE_URL;

npm install helmet cors express-rate-limit

const helmet = require('helmet');
const cors = require('cors');
const rateLimit = require('express-rate-limit');
 
// Security headers
app.use

// Wrapper function
const asyncHandler = (fn) => (req, res, next) => {
 Promise.resolve(fn(req, res, next)).catch

npm install --save-dev jest supertest

const request = require('supertest');
const app = require('./app');
 
describe('GET /api/users', () => {
 it('should return all users'

my-app/
├── src/
│  ├── controllers/
│  │  ├── userController.js
│  │  └── authController.js
│  ├── routes/
│  │  ├── userRoutes.js
│  │  └── authRoutes.js
│  ├── middleware/
│  │  ├── auth.js
│  │  ├── validate.js
│  │  └── errorHandler.js
│  ├── models/
│  │  └── User.js
│  ├── utils/
│  │  └── helpers.js
│  └── app.js
├── .env
├── .gitignore
├── package.json
└── server.js

# Install PM2
npm install -g pm2
 
# Start app
pm2 start server.js --name my-app
 
# Auto-restart on crash
pm2 startup
pm2 save
 
# Monitor
pm2 monit
 
# Logs
pm2 logs