typeahead subscription

[danielGz]

I just stumbled upon some question when thinking about any possible memory leak in my application:
Since the typeahead Observable is provided we never get a chance to unsubscribe from it as the subscription happens inside the directive code, should we need to worry about this?

I implemented my own solution and so far it seems that no negative secondary effects were caused:

 protected asyncActions(): void {
    this.typeaheadSubscription=this.keyUpEventEmitter
      .debounceTime(this.typeaheadWaitMs)
      .mergeMap(() => this.typeahead)
      .subscribe(
        (matches: any[]) => {
          this.finalizeAsyncCall(matches);
        },
        (err: any) => {
          console.error(err);
        }
      );
  }

and inside ngOnDestroy :

public ngOnDestroy(): any {
    this._typeahead.dispose();
    this.typeaheadSubscription.unsubscribe();    
  }

[valorkin]

or like here

ngx-bootstrap/src/dropdown/bs-dropdown-toggle.directive.ts

Lines 50 to 62 in 31cba41

	this._subscriptions.push(this._state
	.isOpenChange.subscribe((value: boolean) => this.isOpen = value));
	// populate disabled state
	this._subscriptions.push(this._state
	.isDisabledChange
	.subscribe((value: boolean) => this.isDisabled = value || null));
	}
	ngOnDestroy(): void {
	for (const sub of this._subscriptions) {
	sub.unsubscribe();
	}
	}

anyway, you are right and this is
a good reason for small PR :)

[danielGz]

Thanks!