Because using multicast with a new Subject is such a common pattern, there is a shortcut in RxJS for this: the publish() operator. This lesson introduces publish() and its variants publishReplay(), publishBehavior(), publishLast(), share(), and shows how they simplify the creation of multicasted Observables.
var shared = Rx.Observable.interval(1000) .do(x => console.log(‘source ‘ + x)) .multicast(new Rx.Subject()) .refCount();
This partten multicast(new Rx.Subject()) to create sharable subject is so common, there is shortcut to doing this: ‘publish()‘:
var shared = Rx.Observable.interval(1000) .do(x => console.log(‘source ‘ + x)) .publish() .refCount();
Also for BehaviourSubject(), AsyncSubject(), ReplaySubject() they all have:
// publish = multicast + Subject // publishReplay = multicast + ReplaySubject // publishBehavior = multicast + BehaviorSubject // publishLast = multicast + AsyncSubject
In fact, publish.refCount() is also common used, so there is another alias for this =.=!!
var shared = Rx.Observable.interval(1000) .do(x => console.log(‘source ‘ + x)) .share(); // share() == publish().refCount() == multiCast(new Rx.Subject()).refCount()
var shared = Rx.Observable.interval(1000) .do(x => console.log(‘source ‘ + x)) .share(); // share = publish().refCount() // publish = multicast + Subject // publishReplay = multicast + ReplaySubject // publishBehavior = multicast + BehaviorSubject // publishLast = multicast + AsyncSubject 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); 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); }, 2000); setTimeout(function () { subA.unsubscribe(); console.log(‘unsubscribed A‘); }, 5000); setTimeout(function () { subB.unsubscribe(); console.log(‘unsubscribed B‘); }, 7000);
时间: 2024-10-09 13:57:16