It is recommended that you emit an error on the application itself. This is useful for centralized error reporting or logging. This also helps to retain the default behavior of Koa for errors. Errors can be emitted using the ctx.app.emit() method:

app.use(async (ctx, next) => {
  try {
    await next();
  } catch (err) {
    ctx.status = err.status || 500;
    ctx.body = err.message;
    ctx.app.emit('error', err, ctx);
  }
});