guard parentNode being null when walking DOM

[richardmonette]

While walking the DOM it is possible that parentNode can become null. As a result, the not null check at line 53 may not guard against all null cases. This can be fixed by moving the check into the while loop conditions.

@tylermercier @celsodantas @nsimmons @patrickdonovan @kurtfunai @qq99

[nsimmons]

Good catch 👍

[tylermercier]

Can you add a test for this?

[qq99]

May be tricky to add a test for this, perhaps detach the DOM node then trigger the event?

[pushrax]

This line could be reduced to

while target != document && target?

which will compile to

while (target !== document && target != null)

[richardmonette]

My rationale was that target != null will cause an error is target is not defined, whereas (I think anyways) that typeof target != "undefined" will return false even if target is not defined. Therefore, if target was undefined, or null, the checked would be false, an not in an error state. That being said, in this context I don't see how target would be undefined, so I agree with your solution. Updated in latest commit, thanks!

[pushrax]

Just for the future, typeof undefined == 'undefined' and typeof something_never_declared == 'undefined' and undefined == null

[richardmonette]

@tylermercier @qq99 I'm going to have to refresh my memory after the holidays, but I'll work on getting a test for this.

[qq99]

Can we ship this as is?

[nsimmons]

I would

[qq99]

wonder if this can be just target and not target?