CODEWITHSUNDEEP
javascriptrxjs
balazs
balazs

Reputation: 5788

How to pause an observable

How to really pause an rxjs observable?

I have the following code:

var pauser = new Rx.Subject();
var animation = new Rx.Subject();
var source = animation.pausableBuffered(pauser);

source
.subscribe(function(frame) {
    console.log('subscribe', frame);
    setTimeout(function() {
        source.resume();
    }, frame.duration);
    source.pause();
});

pauser.onNext(true);
console.log('start');
animation.onNext({ duration: 1000 });
animation.onNext({ duration: 2000 });
animation.onNext({ duration: 2000 });

http://jsfiddle.net/bbvarga/8yvLhjhe/

I expect a start message in the console, right after a subscribe, than 1s break, than one subscribe message, than 2s break, and the last subscribe

but after the one second break I got the two last subscribe message immediately. Seems like I can pause the observable only once.

For those who are interested in what do I want to achieve: I want to have a queue of events, and I want to receive the next event, if some callback is called for the previous one (the event finished. now it's just a simple setTimeout)

Upvotes: 4

Views: 3044

Answers (1)

Jauco
Jauco

Reputation: 1319

pausableBuffered keeps a buffer when paused and drains the buffer when resume is called. What you want looks more like a controlled observable, where you say source.request(1).

See the rxjs docs on backpressure for more info.

var animation = new Rx.Subject();
var source = animation.controlled();

source
.subscribe(function(frame) {
    console.log('new event', frame);
    setTimeout(function() {
        console.log('after timeout', frame);
        source.request(1);
    }, frame.duration);
});

source.request(1);

animation.onNext({ duration: 1000 });
console.log('animation.onNext 1');
animation.onNext({ duration: 2000 });
console.log('animation.onNext 2');
animation.onNext({ duration: 3000 });
console.log('animation.onNext 3')

Upvotes: 2

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