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node_modules/rxjs/_esm5/operators/switchMap.js

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+/** PURE_IMPORTS_START .._OuterSubscriber,.._util_subscribeToResult 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 { OuterSubscriber } from '../OuterSubscriber';
+import { subscribeToResult } from '../util/subscribeToResult';
+/* tslint:enable:max-line-length */
+/**
+ * Projects each source value to an Observable which is merged in the output
+ * Observable, emitting values only from the most recently projected Observable.
+ *
+ * <span class="informal">Maps each value to an Observable, then flattens all of
+ * these inner Observables using {@link switch}.</span>
+ *
+ * <img src="./img/switchMap.png" width="100%">
+ *
+ * Returns an Observable that emits items based on applying a function that you
+ * supply to each item emitted by the source Observable, where that function
+ * returns an (so-called "inner") Observable. Each time it observes one of these
+ * inner Observables, the output Observable begins emitting the items emitted by
+ * that inner Observable. When a new inner Observable is emitted, `switchMap`
+ * stops emitting items from the earlier-emitted inner Observable and begins
+ * emitting items from the new one. 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');
+ * var result = clicks.switchMap((ev) => Rx.Observable.interval(1000));
+ * result.subscribe(x => console.log(x));
+ *
+ * @see {@link concatMap}
+ * @see {@link exhaustMap}
+ * @see {@link mergeMap}
+ * @see {@link switch}
+ * @see {@link switchMapTo}
+ *
+ * @param {function(value: T, ?index: number): ObservableInput} project A function
+ * that, when applied to an item emitted by the source Observable, returns an
+ * 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 the result of applying the
+ * projection function (and the optional `resultSelector`) to each item emitted
+ * by the source Observable and taking only the values from the most recently
+ * projected inner Observable.
+ * @method switchMap
+ * @owner Observable
+ */
+export function switchMap(project, resultSelector) {
+    return function switchMapOperatorFunction(source) {
+        return source.lift(new SwitchMapOperator(project, resultSelector));
+    };
+}
+var SwitchMapOperator = /*@__PURE__*/ (/*@__PURE__*/ function () {
+    function SwitchMapOperator(project, resultSelector) {
+        this.project = project;
+        this.resultSelector = resultSelector;
+    }
+    SwitchMapOperator.prototype.call = function (subscriber, source) {
+        return source.subscribe(new SwitchMapSubscriber(subscriber, this.project, this.resultSelector));
+    };
+    return SwitchMapOperator;
+}());
+/**
+ * We need this JSDoc comment for affecting ESDoc.
+ * @ignore
+ * @extends {Ignored}
+ */
+var SwitchMapSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
+    __extends(SwitchMapSubscriber, _super);
+    function SwitchMapSubscriber(destination, project, resultSelector) {
+        _super.call(this, destination);
+        this.project = project;
+        this.resultSelector = resultSelector;
+        this.index = 0;
+    }
+    SwitchMapSubscriber.prototype._next = function (value) {
+        var result;
+        var index = this.index++;
+        try {
+            result = this.project(value, index);
+        }
+        catch (error) {
+            this.destination.error(error);
+            return;
+        }
+        this._innerSub(result, value, index);
+    };
+    SwitchMapSubscriber.prototype._innerSub = function (result, value, index) {
+        var innerSubscription = this.innerSubscription;
+        if (innerSubscription) {
+            innerSubscription.unsubscribe();
+        }
+        this.add(this.innerSubscription = subscribeToResult(this, result, value, index));
+    };
+    SwitchMapSubscriber.prototype._complete = function () {
+        var innerSubscription = this.innerSubscription;
+        if (!innerSubscription || innerSubscription.closed) {
+            _super.prototype._complete.call(this);
+        }
+    };
+    /** @deprecated internal use only */ SwitchMapSubscriber.prototype._unsubscribe = function () {
+        this.innerSubscription = null;
+    };
+    SwitchMapSubscriber.prototype.notifyComplete = function (innerSub) {
+        this.remove(innerSub);
+        this.innerSubscription = null;
+        if (this.isStopped) {
+            _super.prototype._complete.call(this);
+        }
+    };
+    SwitchMapSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
+        if (this.resultSelector) {
+            this._tryNotifyNext(outerValue, innerValue, outerIndex, innerIndex);
+        }
+        else {
+            this.destination.next(innerValue);
+        }
+    };
+    SwitchMapSubscriber.prototype._tryNotifyNext = function (outerValue, innerValue, outerIndex, innerIndex) {
+        var result;
+        try {
+            result = this.resultSelector(outerValue, innerValue, outerIndex, innerIndex);
+        }
+        catch (err) {
+            this.destination.error(err);
+            return;
+        }
+        this.destination.next(result);
+    };
+    return SwitchMapSubscriber;
+}(OuterSubscriber));
+//# sourceMappingURL=switchMap.js.map