| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| /* tslint:enable:max-line-length */ |
| /** |
| * Projects each source value to the same Observable which is flattened multiple |
| * times with {@link switch} in the output Observable. |
| * |
| * <span class="informal">It's like {@link switchMap}, but maps each value |
| * always to the same inner Observable.</span> |
| * |
| * <img src="./img/switchMapTo.png" width="100%"> |
| * |
| * Maps each source value to the given Observable `innerObservable` regardless |
| * of the source value, and then flattens those resulting Observables into one |
| * single Observable, which is the output Observable. The output Observables |
| * emits values only from the most recently emitted instance of |
| * `innerObservable`. |
| * |
| * @example <caption>Rerun an interval Observable on every click event</caption> |
| * var clicks = Rx.Observable.fromEvent(document, 'click'); |
| * var result = clicks.switchMapTo(Rx.Observable.interval(1000)); |
| * result.subscribe(x => console.log(x)); |
| * |
| * @see {@link concatMapTo} |
| * @see {@link switch} |
| * @see {@link switchMap} |
| * @see {@link mergeMapTo} |
| * |
| * @param {ObservableInput} innerObservable An Observable to replace each value from |
| * the source Observable. |
| * @param {function(outerValue: T, innerValue: I, outerIndex: number, innerIndex: number): any} [resultSelector] |
| * A function to produce the value on the output Observable based on the values |
| * and the indices of the source (outer) emission and the inner Observable |
| * emission. The arguments passed to this function are: |
| * - `outerValue`: the value that came from the source |
| * - `innerValue`: the value that came from the projected Observable |
| * - `outerIndex`: the "index" of the value that came from the source |
| * - `innerIndex`: the "index" of the value from the projected Observable |
| * @return {Observable} An Observable that emits items from the given |
| * `innerObservable` (and optionally transformed through `resultSelector`) every |
| * time a value is emitted on the source Observable, and taking only the values |
| * from the most recently projected inner Observable. |
| * @method switchMapTo |
| * @owner Observable |
| */ |
| export function switchMapTo(innerObservable, resultSelector) { |
| return (source) => source.lift(new SwitchMapToOperator(innerObservable, resultSelector)); |
| } |
| class SwitchMapToOperator { |
| constructor(observable, resultSelector) { |
| this.observable = observable; |
| this.resultSelector = resultSelector; |
| } |
| call(subscriber, source) { |
| return source.subscribe(new SwitchMapToSubscriber(subscriber, this.observable, this.resultSelector)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class SwitchMapToSubscriber extends OuterSubscriber { |
| constructor(destination, inner, resultSelector) { |
| super(destination); |
| this.inner = inner; |
| this.resultSelector = resultSelector; |
| this.index = 0; |
| } |
| _next(value) { |
| const innerSubscription = this.innerSubscription; |
| if (innerSubscription) { |
| innerSubscription.unsubscribe(); |
| } |
| this.add(this.innerSubscription = subscribeToResult(this, this.inner, value, this.index++)); |
| } |
| _complete() { |
| const { innerSubscription } = this; |
| if (!innerSubscription || innerSubscription.closed) { |
| super._complete(); |
| } |
| } |
| _unsubscribe() { |
| this.innerSubscription = null; |
| } |
| notifyComplete(innerSub) { |
| this.remove(innerSub); |
| this.innerSubscription = null; |
| if (this.isStopped) { |
| super._complete(); |
| } |
| } |
| notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
| const { resultSelector, destination } = this; |
| if (resultSelector) { |
| this.tryResultSelector(outerValue, innerValue, outerIndex, innerIndex); |
| } |
| else { |
| destination.next(innerValue); |
| } |
| } |
| tryResultSelector(outerValue, innerValue, outerIndex, innerIndex) { |
| const { resultSelector, destination } = this; |
| let result; |
| try { |
| result = resultSelector(outerValue, innerValue, outerIndex, innerIndex); |
| } |
| catch (err) { |
| destination.error(err); |
| return; |
| } |
| destination.next(result); |
| } |
| } |
| //# sourceMappingURL=switchMapTo.js.map |