[RxJS] RefCount: automatically starting and stopping an execution

var shared = Rx.Observable.interval(1000)
  .do(x => console.log(‘source ‘ + x))
  .multicast(new Rx.Subject())
  .refCount();

var observerA = {
  next: function (x) { console.log(‘A next ‘ + x); },
  error: function (err) { console.log(‘A error ‘ + err); },
  complete: function () { console.log(‘A done‘); },
};

var subA = shared.subscribe(observerA); // start

var observerB = {
  next: function (x) { console.log(‘B next ‘ + x); },
  error: function (err) { console.log(‘B error ‘ + err); },
  complete: function () { console.log(‘B done‘); },
};

var subB;
setTimeout(function () {
  subB = shared.subscribe(observerB); // 1 => 2
}, 2000);

setTimeout(function () {
  subA.unsubscribe(); // 2 => 1
  console.log(‘unsubscribed A‘);
}, 5000);

setTimeout(function () {
  subB.unsubscribe(); // 1 => 0 (stop)
  console.log(‘unsubscribed B‘);
}, 7000);


/*
"source 0"
"A next 0"
"source 1"
"A next 1"
"source 2"
"A next 2"
"B next 2"
"source 3"
"A next 3"
"B next 3"
"source 4"
"A next 4"
"B next 4"
"unsubscribed A"
"source 5"
"B next 5"
"source 6"
"B next 6"
"unsubscribed B"
*/