combineLatest.ts
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import { Observable, ObservableInput } from '../Observable';
import { Scheduler } from '../Scheduler';
import { isScheduler } from '../util/isScheduler';
import { isArray } from '../util/isArray';
import { ArrayObservable } from './ArrayObservable';
import { CombineLatestOperator } from '../operator/combineLatest';
/* tslint:disable:max-line-length */
export function combineLatest<T, T2>(v1: ObservableInput<T>, v2: ObservableInput<T2>, scheduler?: Scheduler): Observable<[T, T2]>;
export function combineLatest<T, T2, T3>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, scheduler?: Scheduler): Observable<[T, T2, T3]>;
export function combineLatest<T, T2, T3, T4>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, scheduler?: Scheduler): Observable<[T, T2, T3, T4]>;
export function combineLatest<T, T2, T3, T4, T5>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, scheduler?: Scheduler): Observable<[T, T2, T3, T4, T5]>;
export function combineLatest<T, T2, T3, T4, T5, T6>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, v6: ObservableInput<T6>, scheduler?: Scheduler): Observable<[T, T2, T3, T4, T5, T6]>;
export function combineLatest<T, R>(v1: ObservableInput<T>, project: (v1: T) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, T2, R>(v1: ObservableInput<T>, v2: ObservableInput<T2>, project: (v1: T, v2: T2) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, T2, T3, R>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, project: (v1: T, v2: T2, v3: T3) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, T2, T3, T4, R>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, project: (v1: T, v2: T2, v3: T3, v4: T4) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, T2, T3, T4, T5, R>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, project: (v1: T, v2: T2, v3: T3, v4: T4, v5: T5) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, T2, T3, T4, T5, T6, R>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, v6: ObservableInput<T6>, project: (v1: T, v2: T2, v3: T3, v4: T4, v5: T5, v6: T6) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T>(array: ObservableInput<T>[], scheduler?: Scheduler): Observable<T[]>;
export function combineLatest<R>(array: ObservableInput<any>[], scheduler?: Scheduler): Observable<R>;
export function combineLatest<T, R>(array: ObservableInput<T>[], project: (...values: Array<T>) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<R>(array: ObservableInput<any>[], project: (...values: Array<any>) => R, scheduler?: Scheduler): Observable<R>;
export function combineLatest<T>(...observables: Array<ObservableInput<T> | Scheduler>): Observable<T[]>;
export function combineLatest<T, R>(...observables: Array<ObservableInput<T> | ((...values: Array<T>) => R) | Scheduler>): Observable<R>;
export function combineLatest<R>(...observables: Array<ObservableInput<any> | ((...values: Array<any>) => R) | Scheduler>): Observable<R>;
/* 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 all the 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 = Rx.Observable.combineLatest(weight, 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 {Observable} observable1 An input Observable to combine with the
* source Observable.
* @param {Observable} observable2 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.
* @param {Scheduler} [scheduler=null] The Scheduler to use for subscribing to
* each input 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.
* @static true
* @name combineLatest
* @owner Observable
*/
export function combineLatest<T, R>(...observables: Array<any | ObservableInput<any> |
Array<ObservableInput<any>> |
(((...values: Array<any>) => R)) |
Scheduler>): Observable<R> {
let project: (...values: Array<any>) => R = null;
let scheduler: Scheduler = null;
if (isScheduler(observables[observables.length - 1])) {
scheduler = <Scheduler>observables.pop();
}
if (typeof observables[observables.length - 1] === 'function') {
project = <(...values: Array<any>) => R>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(observables[0])) {
observables = <Array<Observable<any>>>observables[0];
}
return new ArrayObservable(observables, scheduler).lift(new CombineLatestOperator<T, R>(project));
}