This test is what is failing the CI: https://github.com/nodejs/node/pull/34169/checks?check_run_id=831452407#step:11:10071

Any ideas?

New commit moves away from the count checking and reorganizes the tests using mustCall. This now deviates a bit from the WPT tests but I believe achieves the same thing. If this is not the intended change I can revert the last commit!

One note; I tried implementing this:

{
  const document = new EventTarget();

  const handler = common.mustCall(2)
  // Both should only fire on first event
  document.addEventListener('test', handler, { once: true });
  document.addEventListener('test', handler, { once: true });
  // Fire events
  document.dispatchEvent(new Event('test'));
  document.dispatchEvent(new Event('test'));
}

But it fails - probably my own misunderstanding of common.mustCall. Maybe you two have some in sight here?

It's failing because, unlike EventEmitter, a given function can only be added once. So the second document.addEventListener('test', handler, { once: true }); has no effect. Try changing it to document.addEventListener('test', handler.bind(), { once: true }); and it should hopefully work.

Awesome worked like a charm! Thank you

Hey! I have another test file ready to go. Should I push it to this PR/branch or include it in another branch?

@Ethan-Arrowood ... just push it here. We can do another CI run on this and give it another day to land.

@Ethan-Arrowood could you please squash/fixup the appropriate commits and remove the merge commit, our CI doesn't handle merge commits very well? This looks ready to land to me after a successful CI.

Alright squashed and fixed up your comments.

This pr #33621 introduces some conflicts with test-eventtarget-whatwg-once.js.

I'm pushing another rebase that fixes some of that. I guess this PR needs to be reviewed again

CI: https://ci.nodejs.org/job/node-test-pull-request/34249/

@aduh95 let me know if theres anything else I should do here

@Ethan-Arrowood can you rebase to resolve the git conflict please?

CI: https://ci.nodejs.org/job/node-test-pull-request/34289/

Landed in 7cba786