how to use the delaywhen function from the rxjs library in javascript

The delayWhen function in the rxjs library allows you to delay the emissions of a stream based on the emissions of another stream. It takes a function that returns an observable, and delays the emissions of the source stream until the observable returned from the function emits a value.

Here's an example of how to use delayWhen:

index.tsx
import { fromEvent, interval } from 'rxjs';
import { delayWhen } from 'rxjs/operators';

const clicks$ = fromEvent(document, 'click');
const delayedInterval$ = interval(1000).pipe(
  delayWhen(() => clicks$)
);

delayedInterval$.subscribe(console.log);
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In this example, we create a stream clicks$ that emits whenever the user clicks anywhere on the document. We then create an interval stream that emits a value every second. With delayWhen, we delay the emissions of the interval stream until a click occurs, effectively resetting the interval timer.

Whenever the user clicks, the interval starts over and waits another second before emitting a value.

Note that delayWhen takes a function that returns an observable. In this example, we pass in () => clicks$, which returns the clicks$ stream itself. This means that whenever a click occurs on the clicks$ stream, the delayed emissions from the delayedInterval$ stream will be triggered.