fix #2932: check parent is null for swap delete

[jackielii]

Description

Please describe what changes you made, and why you feel they are necessary. Make sure to include
code examples, where applicable.

Corresponding issue: fix #2932

Testing

Please explain how you tested this change manually, and, if applicable, what new tests you added. If
you're making a change to just the website, you can omit this section.

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded

[Telroshan]

Hey, could you add a test case, just to ensure that the issue happens without your fix when running the test suite, then that your PR fixes it ? (also to prevent any future regression on this), thanks !

Also, as per our contribution guidelines, please target the dev branch for source changes

[jackielii]

Hi @Telroshan ,

I added test, and found out about the outerHTML swap issue. So fixed that and added a test for it as well.

Let me know if you need anything else.

[Telroshan]

Thanks, though if I run your tests locally without your PR's fix (thus with the current library's state), the test seem to already pass 😬

The tests should be setup so that they fail with the current state of the lib, and pass with your fix (to prove the resolution, and ensure we don't introduce regressions in the future).
So in their current state, the 2 new tests appear to be "useless" in the way that they don't fail with the buggy lib behavior in the first place.

It's weird because I don't seem to even get an exception in the console. Didn't spend time investigating this so I can't be of much more help right now unfortunately!

[jackielii]

Hmm, that's weird, I clearly run the tests without the fix and they fail. Maybe it's my last minute clean up. Will check and modify

[jackielii]

hi @Telroshan , I realised I removed the div.remove() because I thought remove parent would remove the div. Turns out not to be the case. so the div.remove() is needed in the test. Should be all good now

[Telroshan]

Yep all good, tests correctly fail now with the current lib's state, then pass with your fix, thanks!