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- import { Observable } from '../Observable';
- import { MonoTypeOperatorFunction } from '../interfaces';
- /**
- * Delays the emission of items from the source Observable by a given time span
- * determined by the emissions of another Observable.
- *
- * <span class="informal">It's like {@link delay}, but the time span of the
- * delay duration is determined by a second Observable.</span>
- *
- * <img src="./img/delayWhen.png" width="100%">
- *
- * `delayWhen` time shifts each emitted value from the source Observable by a
- * time span determined by another Observable. When the source emits a value,
- * the `delayDurationSelector` function is called with the source value as
- * argument, and should return an Observable, called the "duration" Observable.
- * The source value is emitted on the output Observable only when the duration
- * Observable emits a value or completes.
- *
- * Optionally, `delayWhen` takes a second argument, `subscriptionDelay`, which
- * is an Observable. When `subscriptionDelay` emits its first value or
- * completes, the source Observable is subscribed to and starts behaving like
- * described in the previous paragraph. If `subscriptionDelay` is not provided,
- * `delayWhen` will subscribe to the source Observable as soon as the output
- * Observable is subscribed.
- *
- * @example <caption>Delay each click by a random amount of time, between 0 and 5 seconds</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var delayedClicks = clicks.delayWhen(event =>
- * Rx.Observable.interval(Math.random() * 5000)
- * );
- * delayedClicks.subscribe(x => console.log(x));
- *
- * @see {@link debounce}
- * @see {@link delay}
- *
- * @param {function(value: T): Observable} delayDurationSelector A function that
- * returns an Observable for each value emitted by the source Observable, which
- * is then used to delay the emission of that item on the output Observable
- * until the Observable returned from this function emits a value.
- * @param {Observable} subscriptionDelay An Observable that triggers the
- * subscription to the source Observable once it emits any value.
- * @return {Observable} An Observable that delays the emissions of the source
- * Observable by an amount of time specified by the Observable returned by
- * `delayDurationSelector`.
- * @method delayWhen
- * @owner Observable
- */
- export declare function delayWhen<T>(delayDurationSelector: (value: T) => Observable<any>, subscriptionDelay?: Observable<any>): MonoTypeOperatorFunction<T>;
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