How can I subscribe to a promise using rx.js?

Question

I have a function that returns promise.
I want to subscribe to that promise using rx.js in such way that calling of this function will push notifications to all subscribers.

Here is what I have:

var subject = new Rx.Subject();

var subscription = subject.subscribe(
    function (x) { console.log('onNext: ' + x); },
    function (e) { console.log('onError: ' + e.message); },
    function () { console.log('onCompleted'); }
);

//here I want to push first notification
subject.fromPromise(functionThatReturnsPromise()); 

//some code

//here I want to push second notification
subject.fromPromise(functionThatReturnsPromise()); 

As a result subscriber receives only one notification.

How to solve that?

Answer 1

var subject = new Rx.Subject();

var subscription = subject.mergeAll().subscribe(
    function (x) { console.log('onNext: ' + x); },
    function (e) { console.log('onError: ' + e.message); },
    function () { console.log('onCompleted'); }
);

subject.onNext(Rx.Observable.fromPromise(functionThatReturnsPromise()));

//some code

subject.onNext(Rx.Observable.fromPromise(functionThatReturnsPromise()));

The subject here is now a metastream (an observable of observables). And before subscribing to it, we "flatten" it by calling mergeAll() . On the onNext() we are feeding Observables to the subject, that's what makes it a metastream.