CODEWITHSUNDEEP
observableangular5rxjs5
Dániel Kis
Dániel Kis

Reputation: 2631

How to detect unsubscribe in Observer

I wrap a http call to a new Observable, but I cannot detect if the subscription is cancelled:

constructor( @Inject(Http) private http: Http) {
}


...


const observable = Observable.create((observer: Observer<any>) => {
            this.http.post(url, body)
                .subscribe((p) => {
                    observer.next(p.json());
                    observer.complete();
                }, (err) => {
                    observer.error(err);
                    observer.complete();
                });
        });
const subscription = observable.subscribe((r) => { alert("result : "+r); }, (err) => { alert("error occured");}

subscription.unsubscribe(); // if user cancels the request

How can I detect in Observable.create(...) if the user cancels the subscription? I would like to cancel the http post request when the outer Observable is cancelled.

Upvotes: 1

Views: 1690

Answers (1)

Yerkon
Yerkon

Reputation: 4788

You can manually create unsubscribe function like:

 constructor(public http: HttpClient) {
    let url = 'google.kz';

    const observable = Observable.create((observer: Observer<any>) => {
      let cancel: Subscription = this.http.post(url, {})
        .subscribe((p) => {
          observer.next(p);
          observer.complete();
        }, (err) => {
          observer.error(err);
          observer.complete();
        });

      // Provide a way of canceling and disposing the internal observables
      return function unsubscribe() {
        cancel.unsubscribe();
      };
    });

    let unsc = observable.subscribe(data => {
      console.log(data);
    })
    console.log('unsubscribe', unsc);

    unsc.unsubscribe();
  }

So, when you call unsubscribe() function of outer observable, inner observables unsubscribes too depending how it realized

StackBlitz Demo

Upvotes: 3

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