How to debug Node.js applications: a step-by-step guide for beginners

Hi everyone! I just started learning Node.js and am writing my first server on Express. I ran into a problem: my application is not working as I expected. Here's the simplified code: ```javascript const express = require('express'); const app = express(); app.get('/users/:id', (req, res) => { const userId = req.params.id; const user = getUserById(userId); res.json({ user: user }); }); app.listen(3000, () => { console.log('Server running on port 3000'); }); function getUserById(id) { const users = [ { id: 1, name: 'Alice' }, { id: 2, name: 'Bob' } ]; return users.find(u => u.id === id); } ``` I'm making a GET request to `/users/1`, but I always get `{ "user": undefined }`. I don't understand why `find()` is not finding the user. I tried inserting `consol