Copied from #19931(comment)

I guess as of #19831 I could simplify this using optional chaining:

wrapperNode.current &&
wrapperNode.current.contains( document.activeElement )
// =>
wrapperNode.current?.contains( document.activeElement )

What's interesting to me is looking at the other, negated instance of this condition, I sense there's going to be a very common pitfall associated with optional chaining:

If someone treats optional chaining as a way to get to the value by any means necessary, it might be easy to overlook that negating would produce true if the optional chaining aborts early:

const wrapperNode = { current: undefined };
! wrapperNode.current?.contains( document.activeElement );
// true

😯 It's definitely not the expected result.

It seems like in the same category of issues we restrict with this ESLint rule:

https://eslint.org/docs/rules/no-unsafe-negation

I could imagine some improvement to that rule which forbids negation of optional chains.

! wrapperNode.current?.contains() is ! ( wrapperNode.current && wrapperNode.current.contains() ).

It's not wrapperNode.current && ! wrapperNode.current.contains().

We need an eslint rule to help us to not fall into this pitfall.