How to check if anyone is subscribed to EventEmitter in Angular?

Question

There is a EventEmitter:

@Output() edit: EventEmitter<any> = new EventEmitter();

How to check if anyone is subscribed to EventEmitter in Angular?

Answer 1

Angular EventEmitter is an RXJS Subject:

class EventEmitter<T> extends Subject

Therefore you can call the .observers property.

RXJS Source Code

/**
 * A Subject is a special type of Observable that allows values to be
 * multicasted to many Observers. Subjects are like EventEmitters.
 *
 * Every Subject is an Observable and an Observer. You can subscribe to a
 * Subject, and you can call next to feed values as well as error and complete.
 *
 * @class Subject<T>
 */
export class Subject<T> extends Observable<T> implements SubscriptionLike {

  [rxSubscriberSymbol]() {
    return new SubjectSubscriber(this);
  }

  observers: Observer<T>[] = [];

Note on EventEmitter

Rather than using an EventEmitter, consider BehaviorSubject or ReplaySubject.

See: Delegation: EventEmitter or Observable in Angular