import { Observable } from '../Observable';
import { share as higherOrder } from '../operators/share';

/**
 * Returns a new Observable that multicasts (shares) the original Observable. As long as there is at least one
 * Subscriber this Observable will be subscribed and emitting data. When all subscribers have unsubscribed it will
 * unsubscribe from the source Observable. Because the Observable is multicasting it makes the stream `hot`.
 *
 * This behaves similarly to .publish().refCount(), with a behavior difference when the source observable emits complete.
 * .publish().refCount() will not resubscribe to the original source, however .share() will resubscribe to the original source.
 * Observable.of("test").publish().refCount() will not re-emit "test" on new subscriptions, Observable.of("test").share() will
 * re-emit "test" to new subscriptions.
 *
 * <img src="./img/share.png" width="100%">
 *
 * @return {Observable<T>} An Observable that upon connection causes the source Observable to emit items to its Observers.
 * @method share
 * @owner Observable
 */
export function share<T>(this: Observable<T>): Observable<T> {
  return higherOrder()(this) as Observable<T>;
};