Angular - DialogRef - Unsubscribe - Do I need to unsubscribe from afterClosed?

Question

I got asked by one of my colleagues if we need to unsubscribe from the afterClosed() Observable of a Dialog.

We are using the takeUntil pattern to unsubscribe from all Observables on ngOnDestroy().

this.backEvent = fromEvent(window, 'popstate')     .pipe(         takeUntil(this.destroy$)     )     .subscribe(         () => {             this.navigationService.backClicked = true;             this.navigationService.navigateBackToDirectoryCenter();         }     ); 

ngOnDestroy()

ngOnDestroy() {     this.destroy$.next();     this.destroy$.complete(); } 

So is it necessary to unsubscribe from afterClosed() Observable?

dialogRef.afterClosed().subscribe(     (data) => {             console.log(data);         }     }, ); 

or?

dialogRef.afterClosed()     .pipe(         takeUntil(this.destroy$)     )     .subscribe(         (data) => {             console.log(data);         },     ); 

Answer 1

No

You don't need to unsubscribe as the observable itself completes.You can verify the same by adding a finalize block to see whether observable completes itself or not.

import { finalize } from "rxjs/operators"; 

dialogRef   .afterClosed()   .pipe(finalize(() => console.log("completed")))   .subscribe(data => {     console.log(data);   });  

And when you will close the dialog, you will see completed in console, this depicts that you do not need to unsubscribe the observable.