fix(fetch): update response.url correctly

[kettanaito]

• Follows fix(FetchResponse): set urlList #690 #695
• Fixes FetchResponse does not set the urlList #690
• Related to Native fetch response clone misses url nock/nock#2821

Changes

Our Fetch API representation of the response now sets response.url value correctly.

If working with Undici, instead of redefining the url property, it grabs the response internal state and pushes a new entry to its urlList. This way, Interceptors doesn't interfere with Undici's url getter on the response, which is implemented per spec.

Also per spec, response.url will be '' if the Response instance was constructed manually, which is the case for Interceptors. During regular requests, the response urlList becomes a clone of the request's urlList (see this). We cannot do that, so we push a new entry to the list instead.

If working with other Fetch implementations, Interceptors will keep redefining the url property because that is the lowest predictable surface for us (no guarantee those third-party implementations implement urlList at all).

This pull request also modifies the existing tests and adds new response.url compliance tests.

Important

Interceptors will still check if the provided response.url is a valid URL instance. Relative URLs will not work as they never have**. Setting such invalid URLs will be skipped, and response.url will remain an empty string. This is done intentionally to provide a better, spec-aligned experience vs having the user deal with Invalid URL cryptic errors.

[kettanaito]

about: requests must keep response.url value equal to '':

[kettanaito]

Hi, @mikicho 👋 Solving the response.url issue in this one. Could you please take a look at this once you have a minute? Thank you.

[mikicho]

Great! 🚀
verified in nock.

[kettanaito]

Released: v0.38.1 🎉

This has been released in v0.38.1!

• 📄 Release notes
• 📦 npm package

Make sure to always update to the latest version (npm i @mswjs/interceptors@latest) to get the newest features and bug fixes.

---

Predictable release automation by @ossjs/release.