import { Observable, SubscribableOrPromise } from '../Observable';
/**
 * Emits a value from the source Observable only after a particular time span
 * determined by another Observable has passed without another source emission.
 *
 * <span class="informal">It's like {@link debounceTime}, but the time span of
 * emission silence is determined by a second Observable.</span>
 *
 * <img src="./img/debounce.png" width="100%">
 *
 * `debounce` delays values emitted by the source Observable, but drops previous
 * pending delayed emissions if a new value arrives on the source Observable.
 * This operator keeps track of the most recent value from the source
 * Observable, and spawns a duration Observable by calling the
 * `durationSelector` function. The value is emitted only when the duration
 * Observable emits a value or completes, and if no other value was emitted on
 * the source Observable since the duration Observable was spawned. If a new
 * value appears before the duration Observable emits, the previous value will
 * be dropped and will not be emitted on the output Observable.
 *
 * Like {@link debounceTime}, this is a rate-limiting operator, and also a
 * delay-like operator since output emissions do not necessarily occur at the
 * same time as they did on the source Observable.
 *
 * @example <caption>Emit the most recent click after a burst of clicks</caption>
 * var clicks = Rx.Observable.fromEvent(document, 'click');
 * var result = clicks.debounce(() => Rx.Observable.interval(1000));
 * result.subscribe(x => console.log(x));
 *
 * @see {@link audit}
 * @see {@link debounceTime}
 * @see {@link delayWhen}
 * @see {@link throttle}
 *
 * @param {function(value: T): SubscribableOrPromise} durationSelector A function
 * that receives a value from the source Observable, for computing the timeout
 * duration for each source value, returned as an Observable or a Promise.
 * @return {Observable} An Observable that delays the emissions of the source
 * Observable by the specified duration Observable returned by
 * `durationSelector`, and may drop some values if they occur too frequently.
 * @method debounce
 * @owner Observable
 */
export declare function debounce<T>(this: Observable<T>, durationSelector: (value: T) => SubscribableOrPromise<number>): Observable<T>;