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@benlesh @ajcrites
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import { Subject } from './Subject';
import { Subscriber } from './Subscriber';
import { Subscription } from './Subscription';
/**
* A variant of Subject that only emits a value when it completes. It will emit
* its latest value to all its observers on completion.
*
* @class AsyncSubject<T>
*/
export class AsyncSubject<T> extends Subject<T> {
private value: T = null;
private hasNext: boolean = false;
private hasCompleted: boolean = false;
/** @deprecated This is an internal implementation detail, do not use. */
_subscribe(subscriber: Subscriber<any>): Subscription {
if (this.hasError) {
subscriber.error(this.thrownError);
return Subscription.EMPTY;
} else if (this.hasCompleted && this.hasNext) {
subscriber.next(this.value);
subscriber.complete();
return Subscription.EMPTY;
}
return super._subscribe(subscriber);
}
next(value: T): void {
if (!this.hasCompleted) {
this.value = value;
this.hasNext = true;
}
}
error(error: any): void {
if (!this.hasCompleted) {
super.error(error);
}
}
complete(): void {
this.hasCompleted = true;
if (this.hasNext) {
super.next(this.value);
}
super.complete();
}
}
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