Cloudflare Developers•10mo ago

Have a fun one for the Workers team...

Have a fun one for the Workers team... itty-router is staged to release as v5, but we're running into an issue with the direct export signature. Background: An itty Router instance is a Proxy, with a fetch method. This matches the expected { fetch } signature that Cloudflare or Bun expect. However, CF is having issues with the Proxy (Bun is fine with it, for comparison).

const router = Router()

// doesn't work (but should)
export default router

// works
export default {
  fetch: router.fetch
}

// works
export default { ...router }

const router = Router()

// doesn't work (but should)
export default router

// works
export default {
  fetch: router.fetch
}

// works
export default { ...router }

5 Replies

KevinOP•10mo ago

So to me, this suggests that CF has an issue with the Proxy, despite fetch being a first-class property that even destructures as expected.

James•10mo ago

re: Proxy issue, sounds kinda like https://github.com/cloudflare/workerd/issues/1686

KevinOP•10mo ago

Hmmm I get a weird weird/diff error than that:

Uncaught TypeError: (intermediate value)(intermediate value)(intermediate value) is not iterable

Uncaught TypeError: (intermediate value)(intermediate value)(intermediate value) is not iterable

I suspect Cloudflare is checking the export for a particular attribute/signature that's being picked up by the Proxy intercepts (which we use for routing) so it's likely trying to use something that doesn't exist in the way that CF thinks it might. This appears to be because CF is attempting to iterate over an expected { middleware } attribute. Is the code that does this open source? I'd love to PR an explicit check for if middleware not only exists (as it would in this case), but is, in fact, able to be iterated (e.g. NOT a function). for example, the following snippet throws the same error:

export default {
  middleware: () => console.log('test'),
  fetch: () => {},
}

export default {
  middleware: () => console.log('test'),
  fetch: () => {},
}

bun•10mo ago

Should default exports even work?

KevinOP•10mo ago

Isn’t that the established pattern for Workers? So assuming your router matches the expected { fetch } signature that a Worker index expects, directly exporting the router should be no diff. Hono does this as well.

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Have a fun one for the Workers team...