Build HTTP APIs with routing, middleware, validation, controllers, and error handling.
Lessons
Avoid the pitfalls beginners hit most often.
Common Express Mistakes is easiest to learn by reading the example, changing it, and observing the result.
import express from 'express';
const app = express();
app.use(express.json());
app.get('/api/lessons', (req, res) => {
res.json([{ slug: 'express-routing', title: 'Express Routing' }]);
});
app.post('/api/lessons', (req, res) => {
res.status(201).json({ created: true, title: req.body.title });
});
app.listen(process.env.PORT || 3000);Practice the Common Express Mistakes example in a small scratch file, then explain what changed and why.
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