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- "use strict";
- 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 __());
- };
- var tryCatch_1 = require('../util/tryCatch');
- var errorObject_1 = require('../util/errorObject');
- var OuterSubscriber_1 = require('../OuterSubscriber');
- var subscribeToResult_1 = require('../util/subscribeToResult');
- /* tslint:enable:max-line-length */
- /**
- * Recursively projects each source value to an Observable which is merged in
- * the output Observable.
- *
- * <span class="informal">It's similar to {@link mergeMap}, but applies the
- * projection function to every source value as well as every output value.
- * It's recursive.</span>
- *
- * <img src="./img/expand.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 Observable, and then merging those resulting Observables and
- * emitting the results of this merger. *Expand* will re-emit on the output
- * Observable every source value. Then, each output value is given to the
- * `project` function which returns an inner Observable to be merged on the
- * output Observable. Those output values resulting from the projection are also
- * given to the `project` function to produce new output values. This is how
- * *expand* behaves recursively.
- *
- * @example <caption>Start emitting the powers of two on every click, at most 10 of them</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var powersOfTwo = clicks
- * .mapTo(1)
- * .expand(x => Rx.Observable.of(2 * x).delay(1000))
- * .take(10);
- * powersOfTwo.subscribe(x => console.log(x));
- *
- * @see {@link mergeMap}
- * @see {@link mergeScan}
- *
- * @param {function(value: T, index: number) => Observable} project A function
- * that, when applied to an item emitted by the source or the output Observable,
- * returns an Observable.
- * @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of input
- * Observables being subscribed to concurrently.
- * @param {Scheduler} [scheduler=null] The IScheduler to use for subscribing to
- * each projected inner Observable.
- * @return {Observable} An Observable that emits the source values and also
- * result of applying the projection function to each value emitted on the
- * output Observable and and merging the results of the Observables obtained
- * from this transformation.
- * @method expand
- * @owner Observable
- */
- function expand(project, concurrent, scheduler) {
- if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
- if (scheduler === void 0) { scheduler = undefined; }
- concurrent = (concurrent || 0) < 1 ? Number.POSITIVE_INFINITY : concurrent;
- return function (source) { return source.lift(new ExpandOperator(project, concurrent, scheduler)); };
- }
- exports.expand = expand;
- var ExpandOperator = (function () {
- function ExpandOperator(project, concurrent, scheduler) {
- this.project = project;
- this.concurrent = concurrent;
- this.scheduler = scheduler;
- }
- ExpandOperator.prototype.call = function (subscriber, source) {
- return source.subscribe(new ExpandSubscriber(subscriber, this.project, this.concurrent, this.scheduler));
- };
- return ExpandOperator;
- }());
- exports.ExpandOperator = ExpandOperator;
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- var ExpandSubscriber = (function (_super) {
- __extends(ExpandSubscriber, _super);
- function ExpandSubscriber(destination, project, concurrent, scheduler) {
- _super.call(this, destination);
- this.project = project;
- this.concurrent = concurrent;
- this.scheduler = scheduler;
- this.index = 0;
- this.active = 0;
- this.hasCompleted = false;
- if (concurrent < Number.POSITIVE_INFINITY) {
- this.buffer = [];
- }
- }
- ExpandSubscriber.dispatch = function (arg) {
- var subscriber = arg.subscriber, result = arg.result, value = arg.value, index = arg.index;
- subscriber.subscribeToProjection(result, value, index);
- };
- ExpandSubscriber.prototype._next = function (value) {
- var destination = this.destination;
- if (destination.closed) {
- this._complete();
- return;
- }
- var index = this.index++;
- if (this.active < this.concurrent) {
- destination.next(value);
- var result = tryCatch_1.tryCatch(this.project)(value, index);
- if (result === errorObject_1.errorObject) {
- destination.error(errorObject_1.errorObject.e);
- }
- else if (!this.scheduler) {
- this.subscribeToProjection(result, value, index);
- }
- else {
- var state = { subscriber: this, result: result, value: value, index: index };
- this.add(this.scheduler.schedule(ExpandSubscriber.dispatch, 0, state));
- }
- }
- else {
- this.buffer.push(value);
- }
- };
- ExpandSubscriber.prototype.subscribeToProjection = function (result, value, index) {
- this.active++;
- this.add(subscribeToResult_1.subscribeToResult(this, result, value, index));
- };
- ExpandSubscriber.prototype._complete = function () {
- this.hasCompleted = true;
- if (this.hasCompleted && this.active === 0) {
- this.destination.complete();
- }
- };
- ExpandSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
- this._next(innerValue);
- };
- ExpandSubscriber.prototype.notifyComplete = function (innerSub) {
- var buffer = this.buffer;
- this.remove(innerSub);
- this.active--;
- if (buffer && buffer.length > 0) {
- this._next(buffer.shift());
- }
- if (this.hasCompleted && this.active === 0) {
- this.destination.complete();
- }
- };
- return ExpandSubscriber;
- }(OuterSubscriber_1.OuterSubscriber));
- exports.ExpandSubscriber = ExpandSubscriber;
- //# sourceMappingURL=expand.js.map
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