How do I handle JWT authentication errors in Node.js with Express?

How do I handle JWT authentication errors in Node.js with Express?

To handle JWT authentication errors in Node.js with Express, you can use middleware to catch errors and respond appropriately.

Can you show me an example of that middleware?

Sure! Here's a simple middleware function:

function errorHandler(err, req, res, next) {
    if (err.name === 'JsonWebTokenError') {
        return res.status(401).json({ message: 'Invalid token' });
    }
    if (err.name === 'TokenExpiredError') {
        return res.status(401).json({ message: 'Token expired' });
    }
    next(err);
}

What should I do if the token is missing?

You can check for the presence of the token in your request headers and respond with a 401 status if it's missing. Here's an example:

function checkToken(req, res, next) {
    const token = req.headers['authorization'];
    if (!token) {
        return res.status(401).json({ message: 'Token is required' });
    }
    next();
}