How to convert or assign an Observable to a BehaviorSubject so another component can share it

Question

Can someone help me with the code and example of how to convert or assign an Observable to a BehaviorSubject so another component can share it?

Answer 1

To convert or assign an Observable to a BehaviorSubject in Angular (or RxJS), you can subscribe to the Observable and emit its values through the BehaviorSubject. This allows other components to share and react to the data.

Steps to Convert Observable to BehaviorSubject
Create a BehaviorSubject:
Initialize a BehaviorSubject with an initial value (or null if no initial v
alue is needed).

Subscribe to the Observable:
Subscribe to the Observable and use the next method of the BehaviorSubject to emit its values.

Expose the BehaviorSubject as an Observable:
Use the asObservable() method to expose the BehaviorSubject as an Observable for other components to subscribe to.

Example Code
import { BehaviorSubject } from 'rxjs';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
// Example Observable
const sourceObservable$: Observable<number> = new Observable((observer) => {
  observer.next(1);
  observer.next(2);
  observer.next(3);
});
// Convert Observable to BehaviorSubject
const behaviorSubject = new BehaviorSubject<number | null>(null);
sourceObservable$.subscribe({
  next: (value) => behaviorSubject.next(value),
  error: (err) => behaviorSubject.error(err),
  complete: () => behaviorSubject.complete(),
});
// Expose BehaviorSubject as an Observable
const sharedObservable$ = behaviorSubject.asObservable();
// Usage in another component
sharedObservable$.subscribe((value) => {
  console.log('Received value:', value);
});