132 lines
5.1 KiB
JavaScript
132 lines
5.1 KiB
JavaScript
"use strict";
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var __extends = (this && this.__extends) || function (d, b) {
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for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
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function __() { this.constructor = d; }
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d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
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};
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var OuterSubscriber_1 = require('../OuterSubscriber');
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var subscribeToResult_1 = require('../util/subscribeToResult');
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/* tslint:enable:max-line-length */
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/**
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* Combines the source Observable with other Observables to create an Observable
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* whose values are calculated from the latest values of each, only when the
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* source emits.
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*
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* <span class="informal">Whenever the source Observable emits a value, it
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* computes a formula using that value plus the latest values from other input
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* Observables, then emits the output of that formula.</span>
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*
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* <img src="./img/withLatestFrom.png" width="100%">
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*
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* `withLatestFrom` combines each value from the source Observable (the
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* instance) with the latest values from the other input Observables only when
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* the source emits a value, optionally using a `project` function to determine
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* the value to be emitted on the output Observable. All input Observables must
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* emit at least one value before the output Observable will emit a value.
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*
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* @example <caption>On every click event, emit an array with the latest timer event plus the click event</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var timer = Rx.Observable.interval(1000);
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* var result = clicks.withLatestFrom(timer);
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* result.subscribe(x => console.log(x));
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*
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* @see {@link combineLatest}
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*
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* @param {ObservableInput} other An input Observable to combine with the source
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* Observable. More than one input Observables may be given as argument.
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* @param {Function} [project] Projection function for combining values
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* together. Receives all values in order of the Observables passed, where the
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* first parameter is a value from the source Observable. (e.g.
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* `a.withLatestFrom(b, c, (a1, b1, c1) => a1 + b1 + c1)`). If this is not
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* passed, arrays will be emitted on the output Observable.
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* @return {Observable} An Observable of projected values from the most recent
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* values from each input Observable, or an array of the most recent values from
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* each input Observable.
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* @method withLatestFrom
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* @owner Observable
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*/
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function withLatestFrom() {
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var args = [];
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for (var _i = 0; _i < arguments.length; _i++) {
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args[_i - 0] = arguments[_i];
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}
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return function (source) {
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var project;
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if (typeof args[args.length - 1] === 'function') {
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project = args.pop();
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}
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var observables = args;
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return source.lift(new WithLatestFromOperator(observables, project));
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};
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}
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exports.withLatestFrom = withLatestFrom;
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var WithLatestFromOperator = (function () {
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function WithLatestFromOperator(observables, project) {
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this.observables = observables;
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this.project = project;
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}
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WithLatestFromOperator.prototype.call = function (subscriber, source) {
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return source.subscribe(new WithLatestFromSubscriber(subscriber, this.observables, this.project));
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};
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return WithLatestFromOperator;
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}());
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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var WithLatestFromSubscriber = (function (_super) {
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__extends(WithLatestFromSubscriber, _super);
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function WithLatestFromSubscriber(destination, observables, project) {
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_super.call(this, destination);
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this.observables = observables;
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this.project = project;
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this.toRespond = [];
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var len = observables.length;
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this.values = new Array(len);
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for (var i = 0; i < len; i++) {
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this.toRespond.push(i);
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}
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for (var i = 0; i < len; i++) {
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var observable = observables[i];
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this.add(subscribeToResult_1.subscribeToResult(this, observable, observable, i));
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}
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}
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WithLatestFromSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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this.values[outerIndex] = innerValue;
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var toRespond = this.toRespond;
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if (toRespond.length > 0) {
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var found = toRespond.indexOf(outerIndex);
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if (found !== -1) {
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toRespond.splice(found, 1);
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}
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}
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};
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WithLatestFromSubscriber.prototype.notifyComplete = function () {
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// noop
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};
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WithLatestFromSubscriber.prototype._next = function (value) {
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if (this.toRespond.length === 0) {
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var args = [value].concat(this.values);
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if (this.project) {
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this._tryProject(args);
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}
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else {
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this.destination.next(args);
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}
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}
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};
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WithLatestFromSubscriber.prototype._tryProject = function (args) {
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var result;
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try {
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result = this.project.apply(this, args);
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}
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catch (err) {
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this.destination.error(err);
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return;
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}
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this.destination.next(result);
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};
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return WithLatestFromSubscriber;
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}(OuterSubscriber_1.OuterSubscriber));
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//# sourceMappingURL=withLatestFrom.js.map
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