text: import { delayWhen as higherOrder } from '../operators/delayWhen';
  /**
   * 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 function delayWhen(delayDurationSelector, subscriptionDelay) {
      return higherOrder(delayDurationSelector, subscriptionDelay)(this);
  }
  //# sourceMappingURL=delayWhen.js.map