Rxjs number of observable subscriptions

Question

In my Angular 2 app i have many observables and subscriptions. Ofcourse I should unsubscribe when I leave the page, but i\'m trying to find out if it\'s possible to get the

Answer 1

The following utility function may help...

function subscriberCount(sourceObservable: Observable, description: string) {
  let counter = 0;
  return Observable.create((subscriber: Subscriber) => {
    const subscription = sourceObservable.subscribe(subscriber);
    counter++;
    console.log(`${description} subscriptions: ${counter}`);

    return () => {
      subscription.unsubscribe();
      counter--;
      console.log(`${description} subscriptions: ${counter}`);
    }
  });
}

Use it like this:

const timer$ = subscriberCount(Observable.timer(1000), 'Timer');

And the console will log whenever the subscriber count changes