windowWhen

signature: windowWhen(closingSelector: function(): Observable): Observable

Close window at provided time frame emitting observable of collected values from source.

Ultimate RxJS

Examples

Example 1: Open and close window at interval

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+
import { interval, timer } from 'rxjs';
import { windowWhen, tap, mergeAll } from 'rxjs/operators';
//emit immediately then every 1s
const source = timer(0, 1000);
const example = source.pipe(
//close window every 5s and emit observable of collected values from source
windowWhen(() => interval(5000)),
tap(_ => console.log('NEW WINDOW!'))
);
const subscribeTwo = example
.pipe(
//window emits nested observable
mergeAll()
/*
output:
"NEW WINDOW!"
0
1
2
3
4
"NEW WINDOW!"
5
6
7
8
9
*/
)
.subscribe(val => console.log(val));

Additional Resources

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