Observable -> BehaviorSubject

demo.js

// Open http://reactivex.io/rxjs/manual/overview.html to run this code

var timer = new Rx.Observable((obs) => {
  var counter = 0;
  var int = setInterval(() => obs.next(++counter), 1000);
  return () => {
    clearInterval(int);
    obs.complete();
  }
});

var done = new Rx.Subject();
var subject = new Rx.BehaviorSubject();
timer.subscribe(subject);

var counter = 0;

subject.takeUntil(done).subscribe({
  next: (v) => console.log('observerA: ' + v)
});

setTimeout(function() {
  subject.takeUntil(done).subscribe({
    next: (v) => console.log('observerB: ' + v)
  });  
}, 2500);


function kill() {
  done.next(true);
  done.complete();
  return '-- done --'
}

setTimeout(function() {
  kill();
}, 5000);

'-- starting --'