import { asyncScheduler } from '../scheduler/async';
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import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
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import { delayWhen } from './delayWhen';
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import { timer } from '../observable/timer';
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/**
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* Delays the emission of items from the source Observable by a given timeout or
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* until a given Date.
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*
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* <span class="informal">Time shifts each item by some specified amount of
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* milliseconds.</span>
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*
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* 
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*
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* If the delay argument is a Number, this operator time shifts the source
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* Observable by that amount of time expressed in milliseconds. The relative
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* time intervals between the values are preserved.
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*
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* If the delay argument is a Date, this operator time shifts the start of the
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* Observable execution until the given date occurs.
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*
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* ## Examples
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*
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* Delay each click by one second
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*
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* ```ts
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* import { fromEvent, delay } from 'rxjs';
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*
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* const clicks = fromEvent(document, 'click');
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* const delayedClicks = clicks.pipe(delay(1000)); // each click emitted after 1 second
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* delayedClicks.subscribe(x => console.log(x));
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* ```
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*
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* Delay all clicks until a future date happens
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*
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* ```ts
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* import { fromEvent, delay } from 'rxjs';
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*
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* const clicks = fromEvent(document, 'click');
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* const date = new Date('March 15, 2050 12:00:00'); // in the future
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* const delayedClicks = clicks.pipe(delay(date)); // click emitted only after that date
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* delayedClicks.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link delayWhen}
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* @see {@link throttle}
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* @see {@link throttleTime}
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* @see {@link debounce}
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* @see {@link debounceTime}
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* @see {@link sample}
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* @see {@link sampleTime}
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* @see {@link audit}
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* @see {@link auditTime}
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*
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* @param {number|Date} due The delay duration in milliseconds (a `number`) or
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* a `Date` until which the emission of the source items is delayed.
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* @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
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* managing the timers that handle the time-shift for each item.
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* @return A function that returns an Observable that delays the emissions of
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* the source Observable by the specified timeout or Date.
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*/
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export function delay<T>(due: number | Date, scheduler: SchedulerLike = asyncScheduler): MonoTypeOperatorFunction<T> {
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const duration = timer(due, scheduler);
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return delayWhen(() => duration);
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}
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