Workers with itty-router throws an error

Hello! I'm trying to use itty-router in a worker. However, an error is showing when I try to get a path.

X [ERROR] A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from JavaScript to resolve, but has detected that the Promise cannot possibly ever resolve because all code and events related to the Promise's I/O context have already finished.


X [ERROR] Uncaught (in response) Error: The script will never generate a response.

X [ERROR] A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from JavaScript to resolve, but has detected that the Promise cannot possibly ever resolve because all code and events related to the Promise's I/O context have already finished.


X [ERROR] Uncaught (in response) Error: The script will never generate a response.

This is my index.ts

import { Router } from 'itty-router';

const router = Router();

router.get('/', () => {
    return new Response('Hello, world!');
});

router.all('*', () => new Response('404, not found!', { status: 404 }));

export default {
    fetch: router.handle,
};

import { Router } from 'itty-router';

const router = Router();

router.get('/', () => {
    return new Response('Hello, world!');
});

router.all('*', () => new Response('404, not found!', { status: 404 }));

export default {
    fetch: router.handle,
};

Does anyone know why this might be happening?

9 Replies

itaquito•4mo ago

My code is based on this one https://github.com/cloudflare/workers-sdk/blob/main/templates/worker-router/index.js

GitHub

workers-sdk/templates/worker-router/index.js at main · cloudflare/w...

⛅️ Home to Wrangler, the CLI for Cloudflare Workers® - cloudflare/workers-sdk

itaquito•4mo ago

Thanks Solved! It was my version of itty-router. Apparently it only works on ^3.0.12

Kevin•4mo ago

Hey @itaquito! Your issue lays in the fact that during v4, we phased in router.fetch to replace router.handle (to perfectly match up with the export signature of Workers/Bun/etc). During v4, both worked... but with v5, we finally made the breaking change to fully deprecate router.handle. With v5, I'd recommend using AutoRouter to further simplify your code! 🙂 Here's the conversion:

import { AutoRouter } from 'itty-router';

const router = AutoRouter();

router.get('/', () => 'Hello, world!'); // this will turn into a Request

// 404 is automatically handled by AutoRouter

// this is all you need with v5
export default router;

// wrangler currently has a bug requiring this in local dev though...
export default { ...router }

import { AutoRouter } from 'itty-router';

const router = AutoRouter();

router.get('/', () => 'Hello, world!'); // this will turn into a Request

// 404 is automatically handled by AutoRouter

// this is all you need with v5
export default router;

// wrangler currently has a bug requiring this in local dev though...
export default { ...router }

Kevin•4mo ago

https://itty.dev/itty-router/migrations/v4-v5

Migration Guides > v4 to v5 - itty-router - itty.dev

Ultra-small, powerful helpers for modern serverless APIs.

Kevin•4mo ago

We need to add a troubleshooting guide on itty.dev, as this issue comes up often when someone follows an old guide online 🙂 it's the #1 issue by a long shot, so you're in good company! 😄 AutoRouter adds some powerful default effects (with overrides) to Router, namely: - default json formatter for unformatted responses - default error catching - default 404 for missed routes - adds the before and finally middleware/handle stages to clean up global middleware and downstream effects without having to do a .then() chain on the fetch call.

itaquito•4mo ago

Oh! Thanks for your reply! I actually did try AutoRouter, but I only tried exporting it with export default router; and it indeed showed an error.

itaquito•4mo ago

Yeah... Also, when you create an app with npm create cloudflare@latest and select Example router and proxy worker, it just uses an old version of itty-router. Thats why I thought it was the fix

itaquito•4mo ago

But well.. Thanks again! AutoRouter does work if you export it that way!

Kevin•4mo ago

Oh good to know! I’ll see what it takes to get them to update that… maybe I can help! There’s hope on the horizon for the wrangler bug… I saw a PR update on the issue today 🙂

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Workers with itty-router throws an error