delay

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delay
signature: delay(delay: number | Date, scheduler: Scheduler): Observable
Delay emitted values by given time.
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Examples
Example 1: Delay to recognize long press
( StackBlitz )
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import { fromEvent, of } from 'rxjs';
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import { mergeMap, delay, takeUntil } from 'rxjs/operators';
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​
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const mousedown$ = fromEvent(document, 'mousedown');
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const mouseup$ = fromEvent(document, 'mouseup');
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​
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mousedown$
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  .pipe(mergeMap(event => of(event).pipe(delay(700), takeUntil(mouseup$))))
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  .subscribe(event => console.log('Long Press!', event));
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Example 2: Delay for increasing durations
( StackBlitz )
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// RxJS v6+
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import { of, merge } from 'rxjs';
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import { mapTo, delay } from 'rxjs/operators';
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​
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//emit one item
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const example = of(null);
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//delay output of each by an extra second
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const message = merge(
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  example.pipe(mapTo('Hello')),
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  example.pipe(mapTo('World!'), delay(1000)),
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  example.pipe(mapTo('Goodbye'), delay(2000)),
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  example.pipe(mapTo('World!'), delay(3000))
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);
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//output: 'Hello'...'World!'...'Goodbye'...'World!'
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const subscribe = message.subscribe(val => console.log(val));
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Related Recipes
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Additional Resources
​delay 📰 - Official docs
​delay - In Depth Dev Reference
​Transformation operator: delay and delayWhen​
🎥 💵 - André Staltz
📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/delay.ts​
tap / do
delayWhen
Last modified 6mo ago
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Contents
Delay emitted values by given time.
Examples
Related Recipes
Additional Resources