How can I use middleware for authentication in Express?

How can I use middleware for authentication in Express?

You can use middleware in Express to handle authentication by creating a function that checks if a user is authenticated before allowing access to certain routes.

Can you show me a code example of that?

Sure! Here's a simple example:

const express = require('express');
const app = express();

const isAuthenticated = (req, res, next) => {
    if (req.isAuthenticated()) {
        return next();
    }
    res.redirect('/login');
};

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

What if I want to use JWT for authentication?

You can modify the middleware to verify the JWT token. Use a library like jsonwebtoken to decode and verify the token before allowing access.