Angular 14 - Check when all observables are completed-CodePudding

I have a service which contains observable as below

private _actionSaveSubject: BehaviorSubject<string> = new BehaviorSubject<string>( null );
actionSave$: Observable<string> = this._actionSaveSubject.asObservable();

private _actionAfterSaveSubject: BehaviorSubject<string> = new BehaviorSubject<string>( null );

In my components (Component1 and Component2) I inject the service and call the actionSave$ as below

    this.actionService.actionSave$
        .pipe(
            takeUntil( this._unsubscribeAll ),
            skip(1),
            tap(t => {/* TODO saving */ }),
        )
        .subscribe()

In my service I want to know when both the components have finished their actionSave$ observable so that I can call _actionAfterSaveSubject.next(). Is there anyway I can do that?

CodePudding user response：

If I understood you correctly, you want to perform an action after every of your side-effects (inside tap) have run. The only reliable way I see to do this is to feed the observables back to the service and combine them there.

@Service({…})
class YourService {

  private _actionAfterSaveSubject: BehaviorSubject<string> = new BehaviorSubject<string>( null );
  currentSaveSubscription: Subscription;
  actionSaveObservables: Observable<any>[] = [];

  registerActionSaveObservable(saveObservable: Observable<any>) {
    this.actionSaveObservables.push(saveObservable);
    if (this.currentSaveSubscription) {
      this.currentSaveSubscription.unsubscribe()
    }
    this.currentSaveSubscription =
      zip(...actionSaveObservables)
        .subscribe(() => this._actionAfterSaveSubject.next(""))
  }

}

And then register your observables in the component.

this.actionService.registerActionSaveObservable(
    this.actionService.actionSave$
        .pipe(
            takeUntil( this._unsubscribeAll ),
            skip(1),
            tap(t => {/* TODO saving */ }),
        )
);