import {Subject} from '../Subject';
import {ConnectableObservable} from '../observable/ConnectableObservable';
/**
* Returns an Observable that emits the results of invoking a specified selector on items
* emitted by a ConnectableObservable that shares a single subscription to the underlying stream.
*
* <img src="./img/multicast.png" width="100%">
*
* @param {Function} selector - a function that can use the multicasted source stream
* as many times as needed, without causing multiple subscriptions to the source stream.
* Subscribers to the given source will receive all notifications of the source from the
* time of the subscription forward.
* @returns {Observable} an Observable that emits the results of invoking the selector
* on the items emitted by a `ConnectableObservable` that shares a single subscription to
* the underlying stream.
*/
export function multicast<T>(subjectOrSubjectFactory: Subject<T> | (() => Subject<T>)): ConnectableObservable<T> {
let subjectFactory: () => Subject<T>;
if (typeof subjectOrSubjectFactory === 'function') {
subjectFactory = <() => Subject<T>>subjectOrSubjectFactory;
} else {
subjectFactory = function subjectFactory() {
return <Subject<T>>subjectOrSubjectFactory;
};
}
return new ConnectableObservable(this, subjectFactory);
}
|