Irena's stop fetching recipe - for rxjs blog post

close-that-stream-if-no-need.ts

  private unsubscribeDataFetch: Subject<void> = new Subject<void>();

   // polling data till we get what we need and stop 
   fetchData() {
    this.dataService
      .pipe(takeUntil(this.unsubscribeDataFetch))
      .subscribe((data) => actOnData(data));
  }
    
 actOnData(data) {
    if (this.someCondition(data)) {
        this.stopFetchingData();
    }
 }

  stopFetchingData() {
    this.unsubscribeDataFetch.next();
    this.unsubscribeDataFetch.complete();
  }