| import { Operator } from '../Operator'; |
| import { Subscriber } from '../Subscriber'; |
| import { Observable } from '../Observable'; |
| import { empty } from '../observable/empty'; |
| import { MonoTypeOperatorFunction, TeardownLogic } from '../types'; |
| |
| /** |
| * Returns an Observable that will resubscribe to the source stream when the source stream completes, at most count times. |
| * |
| * <span class="informal">Repeats all values emitted on the source. It's like {@link retry}, but for non error cases.</span> |
| * |
| * ![](repeat.png) |
| * |
| * Similar to {@link retry}, this operator repeats the stream of items emitted by the source for non error cases. |
| * Repeat can be useful for creating observables that are meant to have some repeated pattern or rhythm. |
| * |
| * Note: `repeat(0)` returns an empty observable and `repeat()` will repeat forever |
| * |
| * ## Example |
| * Repeat a message stream |
| * ```ts |
| * import { of } from 'rxjs'; |
| * import { repeat, delay } from 'rxjs/operators'; |
| * |
| * const source = of('Repeat message'); |
| * const example = source.pipe(repeat(3)); |
| * example.subscribe(x => console.log(x)); |
| * |
| * // Results |
| * // Repeat message |
| * // Repeat message |
| * // Repeat message |
| * ``` |
| * |
| * Repeat 3 values, 2 times |
| * ```ts |
| * import { interval } from 'rxjs'; |
| * import { repeat, take } from 'rxjs/operators'; |
| * |
| * const source = interval(1000); |
| * const example = source.pipe(take(3), repeat(2)); |
| * example.subscribe(x => console.log(x)); |
| * |
| * // Results every second |
| * // 0 |
| * // 1 |
| * // 2 |
| * // 0 |
| * // 1 |
| * // 2 |
| * ``` |
| * |
| * @see {@link repeatWhen} |
| * @see {@link retry} |
| * |
| * @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 will resubscribe to the source stream when the source stream completes |
| * , at most count times. |
| * @method repeat |
| * @owner Observable |
| */ |
| export function repeat<T>(count: number = -1): MonoTypeOperatorFunction<T> { |
| return (source: Observable<T>) => { |
| if (count === 0) { |
| return empty(); |
| } else if (count < 0) { |
| return source.lift(new RepeatOperator(-1, source)); |
| } else { |
| return source.lift(new RepeatOperator(count - 1, source)); |
| } |
| }; |
| } |
| |
| 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; |
| } |
| source.subscribe(this._unsubscribeAndRecycle()); |
| } |
| } |
| } |