fix: Fire debounced checkNode on leading edge

[JiaboHou]

Taken from @dambusm's fork

This PR fixes issues with checking unmounted nodes and the resulting console errors.

Example console error:

Closes issue: #144

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[CLAassistant]

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[straker]

Thanks for the pr. @dambusm have you noticed any issues with firing on the leading edge? Does getting the results first, but not again until the end of the debounce timer cause any confusion?

[will-ks]

Thanks for the pr. @dambusm have you noticed any issues with firing on the leading edge? Does getting the results first, but not again until the end of the debounce timer cause any confusion?

I'm afraid I haven't had time to test it properly so far, hence not submitting it as a PR myself. I am going to try and grab some time today to play around with it some more and write up some tests.

[straker]

@dambusm any update? If not I think I'm going to merge the pr by end of day.

[will-ks]

I wasn't able to write any tests unfortunately, but I've been using a build with this change on my production project and haven't noticed any ill effects, and the console errors are definitely gone.