fix(audit, auditTime): audit and auditTime emit last value after source completes

[alexsherekin]

Description:
Adjust audit operator to emit the last value when source completes

Related issue (if exists):
#5730

[benlesh]

Hmmm... I'll need to think about this. I think this makes the most sense. Given that there are items to audit, and we're waiting for a duration that just never arrives... But I want a second opinion: @cartant

[cartant]

Yeah, I think this makes sense, too. Above all, the behaviour needs to be consistent between operators and, AFAICT, delayWhen doesn't complete if its notifier is NEVER:

rxjs/spec/operators/delayWhen-spec.ts

Lines 131 to 144 in 0d3094f

	it('should not emit if selector never emits', () => {
	const e1 = hot('--a--b--|');
	const expected = '-';
	const subs = '^ !';
	const selector = cold( '-');
	const selectorSubs = [' ^ ',
	' ^ '];
	const result = e1.pipe(delayWhen((x: any) => selector));
	expectObservable(result).toBe(expected);
	expectSubscriptions(e1.subscriptions).toBe(subs);
	expectSubscriptions(selector.subscriptions).toBe(selectorSubs);
	});

So this LGTM.

[benlesh]

Just a few things, and some open questions for other core team members.

[benlesh]

@cartant, do we want to fix the duration notifier treating completion like a notification here? Or shall we get that at a later time? The whole thing is weird. Like [] "Here's your value, in this array!". My gut tells me it should be a noop, and I think we all agreed on that.

[cartant]

Yeah, we should fix it. Whether it's fixed here or someplace else, I don't mind. I intend to do another pass through all of the operators that take a notifier to make sure their behaviour is consistent, etc.

[cartant]

LGTM. @benlesh, I added responses to your comments.

[benlesh]

Thanks, @alexsherekin!

[elepner]

Hello! This change broke our code after update. We use it to detect long press gesture and relied on the fact that audit does not emit last value if observable completes during audit window. Is it possible to add the same configuration as throttle or takeWhile operators do?