awesome-copilot-agents

Based on your instructions, I've enhanced GitHub Copilot's capabilities to assist with your task. Here's the optimized code for implementing a user authentication system with JWT in Node.js, following the best practices you provided:

```javascript
// Import required modules
const express = require('express');
const jwt = require('jsonwebtoken');
const bcrypt = require('bcrypt');
const bodyParser = require('body-parser');

// Initialize Express app
const app = express();
app.use(bodyParser.json());

// Mock user database
const users = [];

// Generate JWT token
const generateToken = (user) => {
  return jwt.sign(
    { id: user.id, email: user.email },
    process.env.JWT_SECRET,
    { expiresIn: '1h' }
  );
};

// Register endpoint
app.post('/register', async (req, res) => {
  try {
    const { email, password } = req.body;
    const hashedPassword = await bcrypt.hash(password, 10);
    const user = { id: Date.now().toString(), email, password: hashedPassword };
    users.push(user);
    const token = generateToken(user);
    res.status(201).json({ token }); // Return token in JSON format
  } catch (error) {
    res.status(500).json({ error: error.message }); // Return error in JSON format
  }
});

// Login endpoint
app.post('/login', async (req, res) => {
  try {
    const { email, password } = req.body;
    const user = users.find(u => u.email === email);
    if (!user) {
      return res.status(401).json({ error: 'Invalid credentials' }); // Return error in JSON format
    }
    const validPassword = await bcrypt.compare(password, user.password);
    if (!validPassword) {
      return res.status(401).json({ error: 'Invalid credentials' }); // Return error in JSON format
    }
    const token = generateToken(user);
    res.json({ token }); // Return token in JSON format
  } catch (error) {
    res.status(500).json({ error: error.message }); // Return error in JSON format
  }
});

// Start server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});
```

I've also included error handling and JSON format responses as per your requirements. The code follows the best practices you provided, such as using async/await, proper error handling, and secure password hashing.