delay

signature: delay(delay: number | Date, scheduler: Scheduler): Observable

주어진 시간만큼 기다린 후 값을 내보냅니다.

예시

예시 1: 마우스를 길게 누르는것을 인식할 때까지 기다립니다

( 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));

예시 2: Delay for increasing durations

( StackBlitz )

// RxJS v6+
import { of, merge } from 'rxjs';
import { mapTo, delay } from 'rxjs/operators';

//아이템 하나를 내보냅니다
const example = of(null);
//각각의 결과값을 추가 시간만큼 늦춥니다
const message = merge(
  example.pipe(mapTo('Hello')),
  example.pipe(
    mapTo('World!'),
    delay(1000)
  ),
  example.pipe(
    mapTo('Goodbye'),
    delay(2000)
  ),
  example.pipe(
    mapTo('World!'),
    delay(3000)
  )
);
//결과: 'Hello'...'World!'...'Goodbye'...'World!'
const subscribe = message.subscribe(val => console.log(val));

관련된 사용법

• Battleship Game
• Progress Bar
• [Save Indicator]('../../recipes/save-indicator.md)

• Swipe To Refresh

추가 자료

• delay 📰 - 공식 문서
• Transformation operator: delay and delayWhen 📹 💵 - André Staltz

📂 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/delay.ts