49 lines
2.2 KiB
JavaScript
49 lines
2.2 KiB
JavaScript
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import { combineLatest as higherOrder } from '../operators/combineLatest';
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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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export function combineLatest(...observables) {
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return higherOrder(...observables)(this);
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}
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//# sourceMappingURL=combineLatest.js.map
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