How do I handle errors in Express and Koa?

How do I handle errors in Express and Koa?

In Express, you can use middleware to handle errors. Just define an error-handling middleware function with four parameters: err, req, res, and next. In Koa, you can use a try-catch block in your async functions to catch errors.

Can you give me an example of error handling in Express?

Sure! Here's a simple example:

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

What about Koa? How does it differ?

In Koa, you can use a try-catch block like this:

app.use(async (ctx, next) => {
  try {
    await next();
  } catch (err) {
    ctx.status = err.status || 500;
    ctx.body = 'Internal Server Error';
  }
});

Are there any best practices for error handling?

Yes! Always log errors for debugging, send user-friendly messages, and avoid exposing stack traces in production.