Angular 10 : Should I unsubscribe form subscription to valueChanges Observable in ngOnDestroy?

Question

I have a form like this :

this.form = this.fb.group({
  username: ["Put name"],
  address: ["Put address"]
});

And I am listening to username input value :

this.form.controls.username.valueChanges.subscribe(val =>
 //doSomething()
);

Do you think I should add a pipe(takeUntil(this.destroy$)) in order to avoid memory leaks ?

Is there a way to test if I do not unsubscribe when the component is destroyed, the Observable is still living in memory ?

Answer 1

Instead of destroy, you could also do this

public sub: Subscription;

contructor() {
  this.sub = new Subscription();
}

this.sub.add(this.form.controls.username.valueChanges.subscribe(val =>
 //doSomething()
));

ngOnDestroy() {
   this.sub.unsubscribe();
}