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151 lines
5.9 KiB
151 lines
5.9 KiB
"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 ArrayObservable_1 = require('../observable/ArrayObservable'); |
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var isArray_1 = require('../util/isArray'); |
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var OuterSubscriber_1 = require('../OuterSubscriber'); |
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var subscribeToResult_1 = require('../util/subscribeToResult'); |
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var none = {}; |
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/* tslint:enable:max-line-length */ |
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/** |
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* Combines multiple Observables to create an Observable whose values are |
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* calculated from the latest values of each of its input Observables. |
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* |
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* <span class="informal">Whenever any input Observable emits a value, it |
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* computes a formula using the latest values from all the inputs, then emits |
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* the output of that formula.</span> |
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* |
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* <img src="./img/combineLatest.png" width="100%"> |
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* |
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* `combineLatest` combines the values from this Observable with values from |
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* Observables passed as arguments. This is done by subscribing to each |
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* Observable, in order, and collecting an array of each of the most recent |
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* values any time any of the input Observables emits, then either taking that |
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* array and passing it as arguments to an optional `project` function and |
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* emitting the return value of that, or just emitting the array of recent |
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* values directly if there is no `project` function. |
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* |
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* @example <caption>Dynamically calculate the Body-Mass Index from an Observable of weight and one for height</caption> |
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* var weight = Rx.Observable.of(70, 72, 76, 79, 75); |
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* var height = Rx.Observable.of(1.76, 1.77, 1.78); |
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* var bmi = weight.combineLatest(height, (w, h) => w / (h * h)); |
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* bmi.subscribe(x => console.log('BMI is ' + x)); |
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* |
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* // With output to console: |
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* // BMI is 24.212293388429753 |
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* // BMI is 23.93948099205209 |
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* // BMI is 23.671253629592222 |
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* |
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* @see {@link combineAll} |
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* @see {@link merge} |
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* @see {@link withLatestFrom} |
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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] An optional function to project the values from |
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* the combined latest values into a new value 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 combineLatest |
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* @owner Observable |
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*/ |
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function combineLatest() { |
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var observables = []; |
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for (var _i = 0; _i < arguments.length; _i++) { |
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observables[_i - 0] = arguments[_i]; |
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} |
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var project = null; |
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if (typeof observables[observables.length - 1] === 'function') { |
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project = observables.pop(); |
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} |
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// if the first and only other argument besides the resultSelector is an array |
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// assume it's been called with `combineLatest([obs1, obs2, obs3], project)` |
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if (observables.length === 1 && isArray_1.isArray(observables[0])) { |
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observables = observables[0].slice(); |
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} |
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return function (source) { return source.lift.call(new ArrayObservable_1.ArrayObservable([source].concat(observables)), new CombineLatestOperator(project)); }; |
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} |
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exports.combineLatest = combineLatest; |
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var CombineLatestOperator = (function () { |
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function CombineLatestOperator(project) { |
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this.project = project; |
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} |
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CombineLatestOperator.prototype.call = function (subscriber, source) { |
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return source.subscribe(new CombineLatestSubscriber(subscriber, this.project)); |
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}; |
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return CombineLatestOperator; |
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}()); |
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exports.CombineLatestOperator = CombineLatestOperator; |
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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 CombineLatestSubscriber = (function (_super) { |
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__extends(CombineLatestSubscriber, _super); |
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function CombineLatestSubscriber(destination, project) { |
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_super.call(this, destination); |
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this.project = project; |
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this.active = 0; |
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this.values = []; |
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this.observables = []; |
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} |
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CombineLatestSubscriber.prototype._next = function (observable) { |
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this.values.push(none); |
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this.observables.push(observable); |
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}; |
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CombineLatestSubscriber.prototype._complete = function () { |
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var observables = this.observables; |
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var len = observables.length; |
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if (len === 0) { |
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this.destination.complete(); |
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} |
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else { |
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this.active = len; |
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this.toRespond = len; |
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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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}; |
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CombineLatestSubscriber.prototype.notifyComplete = function (unused) { |
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if ((this.active -= 1) === 0) { |
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this.destination.complete(); |
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} |
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}; |
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CombineLatestSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
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var values = this.values; |
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var oldVal = values[outerIndex]; |
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var toRespond = !this.toRespond |
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? 0 |
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: oldVal === none ? --this.toRespond : this.toRespond; |
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values[outerIndex] = innerValue; |
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if (toRespond === 0) { |
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if (this.project) { |
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this._tryProject(values); |
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} |
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else { |
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this.destination.next(values.slice()); |
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} |
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} |
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}; |
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CombineLatestSubscriber.prototype._tryProject = function (values) { |
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var result; |
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try { |
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result = this.project.apply(this, values); |
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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 CombineLatestSubscriber; |
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}(OuterSubscriber_1.OuterSubscriber)); |
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exports.CombineLatestSubscriber = CombineLatestSubscriber; |
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//# sourceMappingURL=combineLatest.js.map
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