Add `cause` to `TimeoutError`

[arty-name]

Fixes https://github.com/sindresorhus/ky/issues/592

This is the simplest approach we could take

[arty-name]

The CI fails on TypeScript not knowing of this property. Locally I see this defined in lib.es2022.error.d.ts, so apparently this was added in ES 2022, which is indirectly confirmed by MDN. Apparently Ky uses a lower version of JS, which is reasonable.

I believe that this second parameter to the Error constructor will be simply ignored by older runtimes, so there should be no danger in adding it.

What would be your preferred way of handling this error in Ky project?

[sindresorhus]

I think it would be more correct to attach the URL as a property on the error. The URL is not really the "cause" of the error.

[arty-name]

Thank you for the quick response!

I see your point, that’s fair enough. I understand that you wouldn’t want to have this in the core.

Personally, I’ll still use cause for practical reason: only cause is supported by tooling. Do you think that this use case justifies adding the beforeTimeout hook?

[sindresorhus]

Personally, I’ll still use cause for practical reason: only cause is supported by tooling.

Not sure what you mean by this, but adding properties to errors has always been the way to add metadata.

[arty-name]

It was, but only the cause gets special treatment by e.g. browser developer tools and Vite/Astro developer overlay. And I am not sure how normative this is, but MDN suggests to use it for metadata.

[sholladay]

The URL alone doesn't seem like a good use of cause.

I would be okay with either or both of the following:

1. Move error.request to error.cause to conform to the expectations of the broader ecosystem and make the metadata more discoverable
2. Add the request method and URL directly to the timeout error message for simple debugging cases

[sindresorhus]

Move error.request to error.cause to conform to the expectations of the broader ecosystem and make the metadata more discoverable

While it is acceptable to use cause for non-errors, I don't think the community conventions for cause are established enough yet for me to want to do this.

Add the request method and URL directly to the timeout error message for simple debugging cases

Let's do this.

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I tried doing a Twitter poll for this, but it ended up being inconclusive: https://x.com/sindresorhus/status/1803812187758080325

[sholladay]

Closing in favor of PR #595

@arty-name what do you think of that solution?

[arty-name]

@sholladay This solution will also resolve my issue, thank you!