doc/api/subjects/asyncsubject.md
Rx.AsyncSubject classRepresents the result of an asynchronous operation. The last value before the OnCompleted notification, or the error received through OnError, is sent to all subscribed observers.
This class inherits both from the Rx.Observable and Rx.Observer classes.
The following example shows caching on the last value produced when followed by an onCompleted notification which makes it available to all subscribers.
var subject = new Rx.AsyncSubject();
var i = 0;
var handle = setInterval(function () {
subject.onNext(i);
if (++i > 3) {
subject.onCompleted();
clearInterval(handle);
}
}, 500);
var subscription = subject.subscribe(
function (x) {
console.log('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: 3
// => Completed
AsyncSubject ConstructorAsyncSubject Instance MethodsRx.AsyncSubject()<a href="#rxasyncsubject">#</a> Ⓢ
Creates a subject that can only receive one value and that value is cached for all future observations.
var subject = new Rx.AsyncSubject();
subject.onNext(42);
subject.onCompleted();
var subscription = subject.subscribe(
function (x) {
console.log('Next: ' + x);
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: 42
// => Completed
Rx.AsyncSubject.prototype.dispose()<a href="#rxasyncsubjectprototypedispose">#</a> Ⓢ
Unsubscribe all observers and release resources.
var subject = new Rx.AsyncSubject();
var subscription = subject.subscribe(
function (x) {
console.log('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
subject.onNext(42);
subject.onCompleted();
// => Next: 42
// => Completed
subject.dispose();
try {
subject.onNext(56);
} catch (e) {
console.log(e.message);
}
// => Object has been disposed
Rx.AsyncSubject.prototype.hasObservers()<a href="#rxasyncsubjectprototypehasobservers">#</a> Ⓢ
Indicates whether the subject has observers subscribed to it.
(Boolean): Returns true if the AsyncSubject has observers, else false.
var subject = new Rx.AsyncSubject();
console.log(subject.hasObservers());
// => false
var subscription = subject.subscribe(
function (x) {
console.log('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
console.log(subject.hasObservers());
// => true