@reactivex/rxjs

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class="source-code line-number raw-source-code"><code class="prettyprint linenums" data-ice="content">import { OuterSubscriber } from '../OuterSubscriber'; import { subscribeToResult } from '../util/subscribeToResult'; /** * Converts a higher-order Observable into a first-order Observable by * subscribing to only the most recently emitted of those inner Observables. * * <span class="informal">Flattens an Observable-of-Observables by dropping the * previous inner Observable once a new one appears.</span> * * <img src="./img/switch.png" width="100%"> * * `switch` subscribes to an Observable that emits Observables, also known as a * higher-order Observable. Each time it observes one of these emitted inner * Observables, the output Observable subscribes to the inner Observable and * begins emitting the items emitted by that. So far, it behaves * like {@link mergeAll}. However, when a new inner Observable is emitted, * `switch` unsubscribes from the earlier-emitted inner Observable and * subscribes to the new inner Observable and begins emitting items from it. It * continues to behave like this for subsequent inner Observables. * * @example <caption>Rerun an interval Observable on every click event</caption> * var clicks = Rx.Observable.fromEvent(document, 'click'); * // Each click event is mapped to an Observable that ticks every second * var higherOrder = clicks.map((ev) => Rx.Observable.interval(1000)); * var switched = higherOrder.switch(); * // The outcome is that `switched` is essentially a timer that restarts * // on every click. The interval Observables from older clicks do not merge * // with the current interval Observable. * switched.subscribe(x => console.log(x)); * * @see {@link combineAll} * @see {@link concatAll} * @see {@link exhaust} * @see {@link mergeAll} * @see {@link switchMap} * @see {@link switchMapTo} * @see {@link zipAll} * * @return {Observable<T>} An Observable that emits the items emitted by the * Observable most recently emitted by the source Observable. * @method switch * @name switch * @owner Observable */ export function _switch() { return this.lift(new SwitchOperator()); } var SwitchOperator = (function () { function SwitchOperator() { } SwitchOperator.prototype.call = function (subscriber, source) { return source._subscribe(new SwitchSubscriber(subscriber)); }; return SwitchOperator; }()); /** * We need this JSDoc comment for affecting ESDoc. * @ignore * @extends {Ignored} */ var SwitchSubscriber = (function (_super) { __extends(SwitchSubscriber, _super); function SwitchSubscriber(destination) { _super.call(this, destination); this.active = 0; this.hasCompleted = false; } SwitchSubscriber.prototype._next = function (value) { this.unsubscribeInner(); this.active++; this.add(this.innerSubscription = subscribeToResult(this, value)); }; SwitchSubscriber.prototype._complete = function () { this.hasCompleted = true; if (this.active === 0) { this.destination.complete(); } }; SwitchSubscriber.prototype.unsubscribeInner = function () { this.active = this.active > 0 ? this.active - 1 : 0; var innerSubscription = this.innerSubscription; if (innerSubscription) { innerSubscription.unsubscribe(); this.remove(innerSubscription); } }; SwitchSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) { this.destination.next(innerValue); }; SwitchSubscriber.prototype.notifyError = function (err) { this.destination.error(err); }; SwitchSubscriber.prototype.notifyComplete = function () { this.unsubscribeInner(); if (this.hasCompleted && this.active === 0) { this.destination.complete(); } }; return SwitchSubscriber; }(OuterSubscriber)); //# sourceMappingURL=switch.js.map</code></pre> </div> <footer class="footer"> Generated by <a href="https://esdoc.org">ESDoc<span data-ice="esdocVersion">(0.4.8)</span></a> </footer> <script src="script/search_index.js"></script> <script src="script/search.js"></script> <script src="script/pretty-print.js"></script> <script src="script/inherited-summary.js"></script> <script src="script/test-summary.js"></script> <script src="script/inner-link.js"></script> <script src="script/patch-for-local.js"></script> </body> </html>