How do I implement authentication in a TypeScript Express app?

How do I implement authentication in a TypeScript Express app?

To implement authentication in a TypeScript Express app, you can use libraries like Passport.js or JWT. Would you like a code example?

Yes, please provide a code example using JWT.

Sure! First, install the necessary packages: npm install jsonwebtoken bcryptjs. Then, create a login route like this:

import express from 'express';
import jwt from 'jsonwebtoken';
import bcrypt from 'bcryptjs';

const app = express();
app.use(express.json());

app.post('/login', async (req, res) => {
    const { username, password } = req.body;
    // Fetch user from database
    const user = await getUserFromDB(username);
    if (user && bcrypt.compareSync(password, user.password)) {
        const token = jwt.sign({ id: user.id }, 'your_jwt_secret', { expiresIn: '1h' });
        return res.json({ token });
    }
    res.status(401).send('Invalid credentials');
});

This is a basic example. Do you need help with anything else?

What about securing routes with the JWT?

To secure routes, you can create a middleware function that verifies the JWT. Here's an example:

const authenticateJWT = (req, res, next) => {
    const token = req.header('Authorization')?.split(' ')[1];
    if (token) {
        jwt.verify(token, 'your_jwt_secret', (err, user) => {
            if (err) {
                return res.sendStatus(403);
            }
            req.user = user;
            next();
        });
    } else {
        res.sendStatus(401);
    }
};

app.get('/protected', authenticateJWT, (req, res) => {
    res.send('This is a protected route!');
});