import { Subject } from './Subject'; import { Subscriber } from './Subscriber'; import { Subscription } from './Subscription'; /** * @class AsyncSubject */ export class AsyncSubject extends Subject { private value: T = null; private hasNext: boolean = false; private hasCompleted: boolean = false; /** @deprecated internal use only */ _subscribe(subscriber: Subscriber): 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(); } }