<script src="https://dir.by/example_lib/rxjs/rx.min.js"></script>

<script>

     // This function runs when subscribe() is called
     function myCode1(observer)
     {
          // synchronously deliver 1, 2, and 3, then complete
          observer.next(1);
          observer.next(2);
          observer.next(3);
          observer.complete();

          // unsubscribe function doesn't need to do anything in this
          // because values are delivered synchronously
          return {unsubscribe() {}};
     }

     // Create a new Observable that will deliver the above sequence
     const sequence = new Rx.Observable(myCode1);

     // execute the Observable and print the result of each notification
     sequence.subscribe({
          next(num) { alert(num); },
          complete() { alert('Finished sequence'); }
     });

     // As result we will see:
     // 1
     // 2
     // 3
     // 'Finished sequence'

</script>

// --- Observable ---
let randomNumGenerator1 = Rx.Observable.create(observer => {
observer.next(Math.random());
});

let observer1 = randomNumGenerator1
.subscribe(num => console.log('observer 1: '+ num));

let observer2 = randomNumGenerator1
.subscribe(num => console.log('observer 2: '+ num));


// ------ BehaviorSubject/ Subject

let randomNumGenerator2 = new Rx.BehaviorSubject(0);
randomNumGenerator2.next(Math.random());

let observer1Subject = randomNumGenerator2
.subscribe(num=> console.log('observer subject 1: '+ num));

let observer2Subject = randomNumGenerator2
.subscribe(num=> console.log('observer subject 2: '+ num));
<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/5.5.3/Rx.min.js"></script>