work.suroh.tk/node_modules/rxjs/operators/combineLatest.js

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2019-12-02 12:22:45 +00:00
"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 ArrayObservable_1 = require('../observable/ArrayObservable');
var isArray_1 = require('../util/isArray');
var OuterSubscriber_1 = require('../OuterSubscriber');
var subscribeToResult_1 = require('../util/subscribeToResult');
var none = {};
/* tslint:enable:max-line-length */
/**
* Combines multiple Observables to create an Observable whose values are
* calculated from the latest values of each of its input Observables.
*
* <span class="informal">Whenever any input Observable emits a value, it
* computes a formula using the latest values from all the inputs, then emits
* the output of that formula.</span>
*
* <img src="./img/combineLatest.png" width="100%">
*
* `combineLatest` combines the values from this Observable with values from
* Observables passed as arguments. This is done by subscribing to each
* Observable, in order, and collecting an array of each of the most recent
* values any time any of the input Observables emits, then either taking that
* array and passing it as arguments to an optional `project` function and
* emitting the return value of that, or just emitting the array of recent
* values directly if there is no `project` function.
*
* @example <caption>Dynamically calculate the Body-Mass Index from an Observable of weight and one for height</caption>
* var weight = Rx.Observable.of(70, 72, 76, 79, 75);
* var height = Rx.Observable.of(1.76, 1.77, 1.78);
* var bmi = weight.combineLatest(height, (w, h) => w / (h * h));
* bmi.subscribe(x => console.log('BMI is ' + x));
*
* // With output to console:
* // BMI is 24.212293388429753
* // BMI is 23.93948099205209
* // BMI is 23.671253629592222
*
* @see {@link combineAll}
* @see {@link merge}
* @see {@link withLatestFrom}
*
* @param {ObservableInput} other An input Observable to combine with the source
* Observable. More than one input Observables may be given as argument.
* @param {function} [project] An optional function to project the values from
* the combined latest values into a new value on the output Observable.
* @return {Observable} An Observable of projected values from the most recent
* values from each input Observable, or an array of the most recent values from
* each input Observable.
* @method combineLatest
* @owner Observable
*/
function combineLatest() {
var observables = [];
for (var _i = 0; _i < arguments.length; _i++) {
observables[_i - 0] = arguments[_i];
}
var project = null;
if (typeof observables[observables.length - 1] === 'function') {
project = observables.pop();
}
// if the first and only other argument besides the resultSelector is an array
// assume it's been called with `combineLatest([obs1, obs2, obs3], project)`
if (observables.length === 1 && isArray_1.isArray(observables[0])) {
observables = observables[0].slice();
}
return function (source) { return source.lift.call(new ArrayObservable_1.ArrayObservable([source].concat(observables)), new CombineLatestOperator(project)); };
}
exports.combineLatest = combineLatest;
var CombineLatestOperator = (function () {
function CombineLatestOperator(project) {
this.project = project;
}
CombineLatestOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new CombineLatestSubscriber(subscriber, this.project));
};
return CombineLatestOperator;
}());
exports.CombineLatestOperator = CombineLatestOperator;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var CombineLatestSubscriber = (function (_super) {
__extends(CombineLatestSubscriber, _super);
function CombineLatestSubscriber(destination, project) {
_super.call(this, destination);
this.project = project;
this.active = 0;
this.values = [];
this.observables = [];
}
CombineLatestSubscriber.prototype._next = function (observable) {
this.values.push(none);
this.observables.push(observable);
};
CombineLatestSubscriber.prototype._complete = function () {
var observables = this.observables;
var len = observables.length;
if (len === 0) {
this.destination.complete();
}
else {
this.active = len;
this.toRespond = len;
for (var i = 0; i < len; i++) {
var observable = observables[i];
this.add(subscribeToResult_1.subscribeToResult(this, observable, observable, i));
}
}
};
CombineLatestSubscriber.prototype.notifyComplete = function (unused) {
if ((this.active -= 1) === 0) {
this.destination.complete();
}
};
CombineLatestSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
var values = this.values;
var oldVal = values[outerIndex];
var toRespond = !this.toRespond
? 0
: oldVal === none ? --this.toRespond : this.toRespond;
values[outerIndex] = innerValue;
if (toRespond === 0) {
if (this.project) {
this._tryProject(values);
}
else {
this.destination.next(values.slice());
}
}
};
CombineLatestSubscriber.prototype._tryProject = function (values) {
var result;
try {
result = this.project.apply(this, values);
}
catch (err) {
this.destination.error(err);
return;
}
this.destination.next(result);
};
return CombineLatestSubscriber;
}(OuterSubscriber_1.OuterSubscriber));
exports.CombineLatestSubscriber = CombineLatestSubscriber;
//# sourceMappingURL=combineLatest.js.map