Example 1: Delay to recognize long press
( StackBlitz )
import { fromEvent, of } from 'rxjs';import { mergeMap, delay, takeUntil } from 'rxjs/operators';const mousedown$ = fromEvent(document, 'mousedown');const mouseup$ = fromEvent(document, 'mouseup');mousedown$.pipe(mergeMap(event => of(event).pipe(delay(700), takeUntil(mouseup$)))).subscribe(event => console.log('Long Press!', event));
Example 2: Delay for increasing durations
( StackBlitz )
// RxJS v6+import { of, merge } from 'rxjs';import { mapTo, delay } from 'rxjs/operators';//emit one itemconst example = of(null);//delay output of each by an extra secondconst message = merge(example.pipe(mapTo('Hello')),example.pipe(mapTo('World!'), delay(1000)),example.pipe(mapTo('Goodbye'), delay(2000)),example.pipe(mapTo('World!'), delay(3000)));//output: 'Hello'...'World!'...'Goodbye'...'World!'const subscribe = message.subscribe(val => console.log(val));
delay 📰 - Official docs
Transformation operator: delay and delayWhen
🎥 💵 - André Staltz
📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/delay.ts