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- /** PURE_IMPORTS_START .._Observable,.._util_subscribeToResult,.._OuterSubscriber PURE_IMPORTS_END */
- var __extends = (this && this.__extends) || function (d, b) {
- for (var p in b)
- if (b.hasOwnProperty(p))
- d[p] = b[p];
- function __() { this.constructor = d; }
- d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
- };
- import { Observable } from '../Observable';
- import { subscribeToResult } from '../util/subscribeToResult';
- import { OuterSubscriber } from '../OuterSubscriber';
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @extends {Ignored}
- * @hide true
- */
- export var DeferObservable = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
- __extends(DeferObservable, _super);
- function DeferObservable(observableFactory) {
- _super.call(this);
- this.observableFactory = observableFactory;
- }
- /**
- * Creates an Observable that, on subscribe, calls an Observable factory to
- * make an Observable for each new Observer.
- *
- * <span class="informal">Creates the Observable lazily, that is, only when it
- * is subscribed.
- * </span>
- *
- * <img src="./img/defer.png" width="100%">
- *
- * `defer` allows you to create the Observable only when the Observer
- * subscribes, and create a fresh Observable for each Observer. It waits until
- * an Observer subscribes to it, and then it generates an Observable,
- * typically with an Observable factory function. It does this afresh for each
- * subscriber, so although each subscriber may think it is subscribing to the
- * same Observable, in fact each subscriber gets its own individual
- * Observable.
- *
- * @example <caption>Subscribe to either an Observable of clicks or an Observable of interval, at random</caption>
- * var clicksOrInterval = Rx.Observable.defer(function () {
- * if (Math.random() > 0.5) {
- * return Rx.Observable.fromEvent(document, 'click');
- * } else {
- * return Rx.Observable.interval(1000);
- * }
- * });
- * clicksOrInterval.subscribe(x => console.log(x));
- *
- * // Results in the following behavior:
- * // If the result of Math.random() is greater than 0.5 it will listen
- * // for clicks anywhere on the "document"; when document is clicked it
- * // will log a MouseEvent object to the console. If the result is less
- * // than 0.5 it will emit ascending numbers, one every second(1000ms).
- *
- * @see {@link create}
- *
- * @param {function(): SubscribableOrPromise} observableFactory The Observable
- * factory function to invoke for each Observer that subscribes to the output
- * Observable. May also return a Promise, which will be converted on the fly
- * to an Observable.
- * @return {Observable} An Observable whose Observers' subscriptions trigger
- * an invocation of the given Observable factory function.
- * @static true
- * @name defer
- * @owner Observable
- */
- DeferObservable.create = function (observableFactory) {
- return new DeferObservable(observableFactory);
- };
- /** @deprecated internal use only */ DeferObservable.prototype._subscribe = function (subscriber) {
- return new DeferSubscriber(subscriber, this.observableFactory);
- };
- return DeferObservable;
- }(Observable));
- var DeferSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
- __extends(DeferSubscriber, _super);
- function DeferSubscriber(destination, factory) {
- _super.call(this, destination);
- this.factory = factory;
- this.tryDefer();
- }
- DeferSubscriber.prototype.tryDefer = function () {
- try {
- this._callFactory();
- }
- catch (err) {
- this._error(err);
- }
- };
- DeferSubscriber.prototype._callFactory = function () {
- var result = this.factory();
- if (result) {
- this.add(subscribeToResult(this, result));
- }
- };
- return DeferSubscriber;
- }(OuterSubscriber));
- //# sourceMappingURL=DeferObservable.js.map
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