How can I handle custom errors in Express.js?

How can I handle custom errors in Express.js?

You can create a custom error class and use middleware to handle errors in your Express app.

Can you show me an example of a custom error class?

Sure! Here's a simple example:

class CustomError extends Error {
    constructor(message, statusCode) {
        super(message);
        this.statusCode = statusCode;
    }
}

How do I use this custom error class in my routes?

You can throw the custom error in your route handlers like this:

app.get('/example', (req, res, next) => {
    throw new CustomError('Not Found', 404);
});

And how do I set up the error handling middleware?

You can set up the middleware at the end of your routes:

app.use((err, req, res, next) => {
    res.status(err.statusCode || 500).json({ message: err.message });
});