delay.md

delay

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

Delay emitted values by given time.

Examples

Example 1: Delay for increasing durations

( StackBlitz | jsBin | jsFiddle )

import { of } from 'rxjs/observable/of';
import { merge } from 'rxjs/observable/merge';
import { mapTo, delay } from 'rxjs/operators';

//emit one item
const example = of(null);
//delay output of each by an extra second
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))
);
//output: 'Hello'...'World!'...'Goodbye'...'World!'
const subscribe = message.subscribe(val => console.log(val));

Related Recipes

• Progress Bar

Additional Resources

• delay 📰 - Official docs
• Transformation operator: delay and delayWhen 📹 💵 - André Staltz

---

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