const dom = $('#operator');
const observable = Rx.Observable.interval(1000).take(5);

const observerA = {
  next: (item) => dom.append('<li>A:' + item + '</li>'),
  error: (err) => dom.append(err),
  complete: () => dom.append('<li>A:done</li>'),
}

observable.subscribe(observerA);

const observerB = {
  next: (item) => dom.append('<li>B:' + item + '</li>'),
  error: (err) => dom.append(err),
  complete: () => dom.append('<li>B:done</li>'),
}

setTimeout(() => {
  observable.subscribe(observerB);
}, 3000);