How do I handle asynchronous errors in Express.js?

How do I handle asynchronous errors in Express.js?

In Express.js, you can handle asynchronous errors by using middleware. You can create a custom error-handling middleware that catches errors from async functions.

Can you show me an example of that?

Sure! You can wrap your async route handlers in a try-catch block or use a utility function to catch errors. Here's a simple example:

app.get('/route', async (req, res, next) => {
    try {
        const data = await someAsyncFunction();
        res.json(data);
    } catch (error) {
        next(error);
    }
});

This way, any error will be passed to the next middleware.

What if I want to handle errors globally?

You can define a global error-handling middleware at the end of your middleware stack. It should have four parameters: err, req, res, and next. Here's an example:

app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).send('Something broke!');
});