What steps are needed to generate an Observable that contains boolean values?

I am looking to create an Observable that can emit a boolean value and be modified by a function.

My attempt was:

showModal$ = new Observable<boolean>();

Unfortunately, this approach did not work as expected.

What I really need is for showModal$ to default to false, with the ability to change its value using a function like:

change() {
  this.showModal$ = !this.showModal$;
}

I am working with Angular2 and would like to subscribe to this Observable from various components.

Could you suggest the best way to accomplish this?

javascriptangulartypescriptrxjsobservable

Answer №1

Utilize a BehaviorSubject for state management

modalState$ = new BehaviorSubject<boolean>(false);

toggleModal() {
  this.modalState$.next(!this.modalState$.getValue());
}

Check out this demonstration in JavaScript:

const { BehaviorSubject, fromEvent } = rxjs;

const modalState$ = new BehaviorSubject(false);

function toggleModal() {
  modalState$.next(!modalState$.getValue());
}

fromEvent(document.getElementById('toggle'), 'click').subscribe(_ => {
  toggleModal();
});

modalState$.subscribe(showModal => {
  console.log(`Modal is now ${showModal ? 'shown' : 'hidden'}`);
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/6.4.0/rxjs.umd.min.js"></script>
<button id="toggle">Toggle</button>

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