shareReplay with local reference

[steven-rothwell]

It would be nice to be able to pipe in a shareReplay(this.myReplaySubject), where this.myReplaySubject is a property of the class. Let's say you have an http GET call that gets items and you utilize shareReplay. You also have an http POST that posts one item. After the successful post, it would be nice to call this.myReplaySubject.next([...this.items, item]). It would then alert all who are subscribed to the GET of the new array of items.

I know there is a way of doing this: https://stackoverflow.com/a/67508863/787958, but there is a major flaw in this and that is you can't pass parameters to the GET call.

It would be nice to be able to share and update the subscribers are changes in the service layer.

[cartant]

In version 7, shareReplay is nothing more than a thin wrapper around share:

rxjs/src/internal/operators/shareReplay.ts

Lines 137 to 142 in cfd2c16

	return share<T>({
	connector: () => new ReplaySubject(bufferSize, windowTime, scheduler),
	resetOnError: true,
	resetOnComplete: false,
	resetOnRefCountZero: refCount
	});

So you can do something similar, but could return some subject - from the connector factory - that's outside of the operator's control.

[steven-rothwell]

I tried creating my own version of share replay where instead of newing up an instance of ReplaySubject, it took a ReplaySubject as a parameter which I set as the connector. I then would pass my local ReplaySubject as that parameter. It worked at first and the subscribers shared the initial value. But, if I called localReplay.next(newValue) elsewhere in my service layer, the subscribers were not notified of the newValue.

[cartant]

FWIW, if you allow the subject to complete, nexting it will be ineffectual.