Example 1: empty immediately completes
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+import { empty } from 'rxjs';//output: 'Complete!'const subscribe = empty().subscribe({next: () => console.log('Next'),complete: () => console.log('Complete!')});
Example 2: empty with timer
( StackBlitz )
// RxJS v6+import { interval, fromEvent, merge, empty } from 'rxjs';import { switchMap, scan, takeWhile, startWith, mapTo } from 'rxjs/operators';const countdownSeconds = 10;const setHTML = id => val => (document.getElementById(id).innerHTML = val);const pauseButton = document.getElementById('pause');const resumeButton = document.getElementById('resume');const interval$ = interval(1000).pipe(mapTo(-1));const pause$ = fromEvent(pauseButton, 'click').pipe(mapTo(false));const resume$ = fromEvent(resumeButton, 'click').pipe(mapTo(true));const timer$ = merge(pause$, resume$).pipe(startWith(true),// if timer is paused return empty observableswitchMap(val => (val ? interval$ : empty())),scan((acc, curr) => (curr ? curr + acc : acc), countdownSeconds),takeWhile(v => v >= 0)).subscribe(setHTML('remaining'));
empty 📰 - Official docs
Creation operators: empty, never, and throw
🎥 💵 - André Staltz
📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/observable/EmptyObservable.ts