Mocked fetch throws a DOMException when executing with an already aborted signal

[valeriobelli]

Hi all!

While executing tests in one of my private repositories, I've seen a weird behaviour which differs from the expected behaviour of native fetch.

When executing the fetch function with an already aborted signal, normalizeRequest (https://github.com/jefflau/jest-fetch-mock/blob/master/src/index.js#L123-L142) throws a DOMException. However, since this function is synchronous, the Error bubbles up without having the chance to intercept its failure with a rejected Promise as it happens with the native implementation. As you can imagine, the result is failing tests.

I'm wondering: is it intended behaviour?

Here, you can find a repo with the reproduction step of what I intend. I've put both the expected and unexpected behaviours.

I am available to help you. 😄