RxJS - Multicasting Operator publishBehavior

publishBehaviour make use of BehaviourSubject, and returns ConnectableObservable. The connect() method has to be used to subscribe to the observable created.

Syntax

publishBehaviour(defaultvalue)

Example

import { interval} from 'rxjs';
import { take, publishBehavior} from 'rxjs/operators';

let observer = interval(1000).pipe(
   take(5),
   publishBehavior(4)
);
const subscribe_one = observer.subscribe(
   x => console.log("Value from Sub1 = "+x)
);
const subscribe_two = observer.subscribe(
   x => console.log("Value from Sub2 = "+x)
);
observer.connect();
console.log("After 2 seconds");
setTimeout(() => {
   const subscribe_three = observer.subscribe(
      x => console.log("Value from Sub3 = "+x)
   );
}, 2000);

Output

The default value will be displayed first and later the value from the observable.