repeat.ts
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import { Operator } from '../Operator';
import { Subscriber } from '../Subscriber';
import { Observable } from '../Observable';
import { EmptyObservable } from '../observable/EmptyObservable';
import { TeardownLogic } from '../Subscription';
/**
* Returns an Observable that repeats the stream of items emitted by the source Observable at most count times,
* on a particular Scheduler.
*
* <img src="./img/repeat.png" width="100%">
*
* @param {Scheduler} [scheduler] the Scheduler to emit the items on.
* @param {number} [count] the number of times the source Observable items are repeated, a count of 0 will yield
* an empty Observable.
* @return {Observable} an Observable that repeats the stream of items emitted by the source Observable at most
* count times.
* @method repeat
* @owner Observable
*/
export function repeat<T>(this: Observable<T>, count: number = -1): Observable<T> {
if (count === 0) {
return new EmptyObservable<T>();
} else if (count < 0) {
return this.lift(new RepeatOperator(-1, this));
} else {
return this.lift(new RepeatOperator(count - 1, this));
}
}
class RepeatOperator<T> implements Operator<T, T> {
constructor(private count: number,
private source: Observable<T>) {
}
call(subscriber: Subscriber<T>, source: any): TeardownLogic {
return source.subscribe(new RepeatSubscriber(subscriber, this.count, this.source));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class RepeatSubscriber<T> extends Subscriber<T> {
constructor(destination: Subscriber<any>,
private count: number,
private source: Observable<T>) {
super(destination);
}
complete() {
if (!this.isStopped) {
const { source, count } = this;
if (count === 0) {
return super.complete();
} else if (count > -1) {
this.count = count - 1;
}
this.unsubscribe();
this.isStopped = false;
this.closed = false;
source.subscribe(this);
}
}
}