passive-subscriber.js

class MyService {

  constructor() {
    this._producer = Rx.Observable.interval(1000)
      .publish();
  }

  private _producer: Rx.ConnectableObservable<number>;

  startItUp(): Rx.Observable<number> {
    return this._producer.refCount();
  }

  get passiveValues(): Rx.Observable<string> {
    return this._producer.mapTo("foo");
  }
}

// USAGE

const service = new MyService();
let subscription: Rx.Subscription;

service.passiveValues
  .subscribe(x => console.log(`Passive value: ${x}`));

setTimeout(() => {
  console.log("START TIMER FIRED");
  subscription = service.startItUp()
    .subscribe(x => console.log(`active starter: ${x}`));
}, 5000);

setTimeout(() => {
  console.log("END TIMER FIRED");
  subscription.unsubscribe();
}, 8000);

// OUTPUT

/*
START TIMER FIRED
Passive value: foo
active starter: 0
Passive value: foo
active starter: 1
END TIMER FIRED
*/