how to unsubscribe for an observable

Question

I have an angular application where I am reading a file and processing it and this processing is part of observable. I have a service which returns the observable an (ngbus

Answer 1

You must unsubscribe from the subscription, not the observable:

processItems() {
    const ngbusy = this.myservice.observable.subscribe(items => {
        // perform some business logic 


        // unsubscribe at some point...
        ngbusy.unsubscribe();
    });

    // this will unsubscribe immediately...
    ngbusy.unsubscribe();

}

Answer 2

This is a good approach using takeuntil and ngUnsubscribe

private ngUnsubscribe: Subject = new Subject();

ngOnInit() {
  this.myThingService
    .getThings()
    .takeUntil(this.ngUnsubscribe)
    .subscribe((things) => console.log(things));
  /* if using lettable operators in rxjs ^5.5.0
      this.myThingService.getThings()
          .pipe(takeUntil(this.ngUnsubscribe))
          .subscribe(things => console.log(things));
      */
  this.myThingService
    .getOtherThings()
    .takeUntil(this.ngUnsubscribe)
    .subscribe((things) => console.log(things));
}
ngOnDestroy() {
  this.ngUnsubscribe.next();
  this.ngUnsubscribe.complete();
}