Express.js Middleware Pattern

1const express = require('express');
2const app = express();
3 
4const logger = (req, res, next) => {
5  console.log(`${req.method} ${req.url}`);
6  next();
7};
8 
9const authenticate = (req, res, next) => {
10  const token = req.headers.authorization;
11  if (!token) {
12    return res.status(401).json({ error: 'Unauthorized' });
13  }
14  req.user = { id: 1, name: 'John' };
15  next();
16};
17 
18app.use(logger);
19app.use('/api', authenticate);
20 
21app.get('/api/profile', (req, res) => {
22  res.json(req.user);
23});
24 
25app.listen(3000);