55 lines
2.4 KiB
JavaScript
55 lines
2.4 KiB
JavaScript
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import { connectableObservableDescriptor } from '../observable/ConnectableObservable';
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/* tslint:enable:max-line-length */
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/**
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* Returns an Observable that emits the results of invoking a specified selector on items
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* emitted by a ConnectableObservable that shares a single subscription to the underlying stream.
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*
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* <img src="./img/multicast.png" width="100%">
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*
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* @param {Function|Subject} subjectOrSubjectFactory - Factory function to create an intermediate subject through
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* which the source sequence's elements will be multicast to the selector function
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* or Subject to push source elements into.
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* @param {Function} [selector] - Optional selector function that can use the multicasted source stream
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* as many times as needed, without causing multiple subscriptions to the source stream.
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* Subscribers to the given source will receive all notifications of the source from the
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* time of the subscription forward.
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* @return {Observable} An Observable that emits the results of invoking the selector
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* on the items emitted by a `ConnectableObservable` that shares a single subscription to
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* the underlying stream.
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* @method multicast
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* @owner Observable
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*/
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export function multicast(subjectOrSubjectFactory, selector) {
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return function multicastOperatorFunction(source) {
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let subjectFactory;
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if (typeof subjectOrSubjectFactory === 'function') {
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subjectFactory = subjectOrSubjectFactory;
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}
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else {
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subjectFactory = function subjectFactory() {
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return subjectOrSubjectFactory;
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};
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}
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if (typeof selector === 'function') {
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return source.lift(new MulticastOperator(subjectFactory, selector));
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}
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const connectable = Object.create(source, connectableObservableDescriptor);
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connectable.source = source;
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connectable.subjectFactory = subjectFactory;
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return connectable;
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};
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}
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export class MulticastOperator {
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constructor(subjectFactory, selector) {
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this.subjectFactory = subjectFactory;
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this.selector = selector;
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}
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call(subscriber, source) {
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const { selector } = this;
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const subject = this.subjectFactory();
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const subscription = selector(subject).subscribe(subscriber);
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subscription.add(source.subscribe(subject));
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return subscription;
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}
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}
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//# sourceMappingURL=multicast.js.map
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