If I have this class with a subject that emits a single value during its life:
export class MyClass {
myEmitter$: Subject<void> = new Subject();
someMethod(){
this.myEmitter$.next();
this.myEmitter$.complete();
}
}
and then in another class:
this.instanceOfMyClass.myEmitter.subscribe();
Should I unsubscribe from instanceOfMyClass.myEmitter$, given that the subject completes after emitting?
When you call complete on the subject, any subscribers will be automatically unsubscribed.
If you look at the source for the subject's complete method:
complete() {
if (this.closed) {
throw new ObjectUnsubscribedError();
}
this.isStopped = true;
const { observers } = this;
const len = observers.length;
const copy = observers.slice();
for (let i = 0; i < len; i++) {
copy[i].complete();
}
this.observers.length = 0;
}
You'll see that the subject calls complete on each of its observers. And the Observable Contract states that:
When an Observable issues an [error] or [complete] notification to its observers, this ends the subscription. Observers do not need to issue an [unsubscribe] notification to end subscriptions that are ended by the Observable in this way.
