express-guide

Guide Express.js

Workflow

1. Initialiser le projet

mkdir my-api && cd my-api
npm init -y
npm install express helmet cors morgan compression express-rate-limit
npm install zod jsonwebtoken bcryptjs
npm install -D typescript ts-node @types/express @types/node nodemon jest supertest

Structure recommandée (feature-based) :

src/
  app.ts          ← config Express, middleware globaux
  server.ts       ← écoute HTTP + graceful shutdown
  routes/         ← index + un fichier par ressource
  controllers/    ← extraction req/res, appel service
  services/       ← logique métier (testable)
  middleware/     ← auth, validate, errorHandler
  models/         ← schémas DB (Prisma / Mongoose)
  utils/          ← helpers, logger, asyncHandler
  types/          ← interfaces TS globales

2. Configurer app.ts avec les middleware globaux

import express from 'express';
import helmet from 'helmet';
import cors from 'cors';
import morgan from 'morgan';
import compression from 'compression';
import rateLimit from 'express-rate-limit';
import { errorHandler } from './middleware/errorHandler';
import { router } from './routes';

const app = express();

app.use(helmet());
app.use(cors({ origin: process.env.ALLOWED_ORIGINS?.split(',') }));
app.use(express.json({ limit: '1mb' }));
app.use(morgan('combined'));
app.use(compression());
app.use(rateLimit({ windowMs: 15 * 60 * 1000, max: 100 }));

app.use('/api/v1', router);

// Error handler TOUJOURS en dernier
app.use(errorHandler);

export { app };

3. Router modulaire par ressource

// routes/users.ts
import { Router } from 'express';
import { authenticate } from '../middleware/auth';
import { validate } from '../middleware/validate';
import { createUserSchema } from '../schemas/user.schema';
import { createUser, getUserById } from '../controllers/user.controller';

const router = Router();

router.post('/', validate(createUserSchema), createUser);
router.get('/:id', authenticate, getUserById);

export { router as userRouter };