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

To use the exhaustAll() function from the rxjs library in JavaScript, you first need to import it from the library. exhaustAll() is used in combination with higher-order observables, which are observables that emit other observables.

Here's an example of how to use exhaustAll():

index.tsx
import { from, interval } from 'rxjs';
import { exhaustAll, map, take } from 'rxjs/operators';

const source$ = from([1, 2, 3]);

const highOrder$ = source$.pipe(
  map((value) => interval(1000).pipe(
    map((innerValue) => `${value} ${innerValue}`),
    take(2),
  )),
);

highOrder$.pipe(exhaustAll()).subscribe(console.log);
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In this example, we're creating a source observable source$ that emits the values 1, 2, and 3. We then use the map() operator to transform each of these values into an interval observable that emits a value every second.

Next, we use the take() operator to limit each of these interval observables to emit only two values.

Finally, we use the exhaustAll() operator to subscribe to these interval observables in sequence. This means that if a new interval observable is emitted before the previous one has completed, it will be ignored until the previous one completes.

The output of this example will be:

index.tsx
1 0
1 1
2 0
2 1
3 0
3 1
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This is because the exhaustAll() operator ensures that all the values emitted by the inner interval observables are subscribed to and emitted in sequence.