Middleware is not catching the error (Deno 2/Hono)

[cvermeer579]

Dear Hono Team,

I'm trying to implement a middleware to catch errors and log the error details, including the stack trace, to a file. However, I'm encountering an issue where the error is not caught in the middleware's catch block.
Below is a simplified version of my code:

import { Hono } from 'https://deno.land/x/hono@v4.3.11/mod.ts';
const app = new Hono();

// Middleware for error handling
app.use('/*', async (context, next) => {
    try {
        console.log('Entering try block');
        await next();
    } catch (e) {
        console.log('Error caught:');
        console.error('Error details:', e);
    }
});

// Route that throws an error
app.get('/error', async (c, next) => {
    throw new Error('This is a test error');
});

// Start the server
Deno.serve({ port: 3030 }, app.fetch);
export default app;

When I call the /error route, I see the message "Entering try block" in the console, but the error is not being caught as expected, and "Error caught" is never logged.
I'm using Deno version 2.0.0-rc.10 and Hono version v4.3.11.

Is there something I might be missing in the error handling setup, or is this a known issue with Deno or Hono?

Thank you for your assistance!

Best regards,
Cornelis

[Dexus]

you should use app.onError

app.onError((err, c) => {
  if (err instanceof HTTPException) {
    // Get the custom response
    console.log("HTTPException", err);
    return err.getResponse();
  }

   if (err instanceof Error) {
    // Get the custom response
    console.log("Error", err);
    return err.toString();
  }

  //...
})

[cvermeer579]

Thank you, Dexus, for your guidance - it worked perfectly!

I've attached the final source code for anyone who might face the same issue. TypeScript requires specific return types for error handling.

import { Hono, HTTPException } from 'https://deno.land/x/hono@v4.3.11/mod.ts';

const app = new Hono();

app.onError((err, c) => {
    if (err instanceof HTTPException) {
        // Log the HTTPException error
        console.log('HTTPException', err);
        // Return the custom response from the exception
        return c.json({ error: err.message }, err.status); // Ensure a valid response is returned
    }

    if (err instanceof Error) {
        // Log the general error
        console.log('Error', err);
        // Return a text response with the error message and a 500 status code
        return c.text(`Error: ${err.message}`, 500); // Ensure a valid response is returned
    }

    // Fallback response for unknown errors
    return c.text('An unknown error occurred', 500);
});

app.get('/error', (c) => {
    throw new Error('Try this error');
});

// Start the server
Deno.serve({ port: 3030 }, app.fetch);

export default app;

Thanks again for your prompt response!