| import { Operator } from '../Operator'; |
| import { Subscriber } from '../Subscriber'; |
| import { Observable } from '../Observable'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { InnerSubscriber } from '../InnerSubscriber'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types'; |
| |
| /* tslint:disable:max-line-length */ |
| export function withLatestFrom<T, R>(project: (v1: T) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, R>(source2: O2, project: (v1: T, v2: ObservedValueOf<O2>) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, R>(v2: O2, v3: O3, project: (v1: T, v2: ObservedValueOf<O2>, v3: ObservedValueOf<O3>) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>, R>(v2: O2, v3: O3, v4: O4, project: (v1: T, v2: ObservedValueOf<O2>, v3: ObservedValueOf<O3>, v4: ObservedValueOf<O4>) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>, O5 extends ObservableInput<any>, R>(v2: O2, v3: O3, v4: O4, v5: O5, project: (v1: T, v2: ObservedValueOf<O2>, v3: ObservedValueOf<O3>, v4: ObservedValueOf<O4>, v5: ObservedValueOf<O5>) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>, O5 extends ObservableInput<any>, O6 extends ObservableInput<any>, R>(v2: O2, v3: O3, v4: O4, v5: O5, v6: O6, project: (v1: T, v2: ObservedValueOf<O2>, v3: ObservedValueOf<O3>, v4: ObservedValueOf<O4>, v5: ObservedValueOf<O5>, v6: ObservedValueOf<O6>) => R): OperatorFunction<T, R>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>>(source2: O2): OperatorFunction<T, [T, ObservedValueOf<O2>]>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>>(v2: O2, v3: O3): OperatorFunction<T, [T, ObservedValueOf<O2>, ObservedValueOf<O3>]>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>>(v2: O2, v3: O3, v4: O4): OperatorFunction<T, [T, ObservedValueOf<O2>, ObservedValueOf<O3>, ObservedValueOf<O4>]>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>, O5 extends ObservableInput<any>>(v2: O2, v3: O3, v4: O4, v5: O5): OperatorFunction<T, [T, ObservedValueOf<O2>, ObservedValueOf<O3>, ObservedValueOf<O4>, ObservedValueOf<O5>]>; |
| export function withLatestFrom<T, O2 extends ObservableInput<any>, O3 extends ObservableInput<any>, O4 extends ObservableInput<any>, O5 extends ObservableInput<any>, O6 extends ObservableInput<any>>(v2: O2, v3: O3, v4: O4, v5: O5, v6: O6): OperatorFunction<T, [T, ObservedValueOf<O2>, ObservedValueOf<O3>, ObservedValueOf<O4>, ObservedValueOf<O5>, ObservedValueOf<O6>]>; |
| export function withLatestFrom<T, R>(...observables: Array<ObservableInput<any> | ((...values: Array<any>) => R)>): OperatorFunction<T, R>; |
| export function withLatestFrom<T, R>(array: ObservableInput<any>[]): OperatorFunction<T, R>; |
| export function withLatestFrom<T, R>(array: ObservableInput<any>[], project: (...values: Array<any>) => R): OperatorFunction<T, R>; |
| |
| /* tslint:enable:max-line-length */ |
| |
| /** |
| * Combines the source Observable with other Observables to create an Observable |
| * whose values are calculated from the latest values of each, only when the |
| * source emits. |
| * |
| * <span class="informal">Whenever the source Observable emits a value, it |
| * computes a formula using that value plus the latest values from other input |
| * Observables, then emits the output of that formula.</span> |
| * |
| * ![](withLatestFrom.png) |
| * |
| * `withLatestFrom` combines each value from the source Observable (the |
| * instance) with the latest values from the other input Observables only when |
| * the source emits a value, optionally using a `project` function to determine |
| * the value to be emitted on the output Observable. All input Observables must |
| * emit at least one value before the output Observable will emit a value. |
| * |
| * ## Example |
| * On every click event, emit an array with the latest timer event plus the click event |
| * ```ts |
| * import { fromEvent, interval } from 'rxjs'; |
| * import { withLatestFrom } from 'rxjs/operators'; |
| * |
| * const clicks = fromEvent(document, 'click'); |
| * const timer = interval(1000); |
| * const result = clicks.pipe(withLatestFrom(timer)); |
| * result.subscribe(x => console.log(x)); |
| * ``` |
| * |
| * @see {@link combineLatest} |
| * |
| * @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] Projection function for combining values |
| * together. Receives all values in order of the Observables passed, where the |
| * first parameter is a value from the source Observable. (e.g. |
| * `a.pipe(withLatestFrom(b, c), map(([a1, b1, c1]) => a1 + b1 + c1))`). If this is not |
| * passed, arrays will be emitted 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 withLatestFrom |
| * @owner Observable |
| */ |
| export function withLatestFrom<T, R>(...args: Array<ObservableInput<any> | ((...values: Array<any>) => R)>): OperatorFunction<T, R> { |
| return (source: Observable<T>) => { |
| let project: any; |
| if (typeof args[args.length - 1] === 'function') { |
| project = args.pop(); |
| } |
| const observables = <Observable<any>[]>args; |
| return source.lift(new WithLatestFromOperator(observables, project)); |
| }; |
| } |
| |
| class WithLatestFromOperator<T, R> implements Operator<T, R> { |
| constructor(private observables: Observable<any>[], |
| private project?: (...values: any[]) => Observable<R>) { |
| } |
| |
| call(subscriber: Subscriber<R>, source: any): any { |
| return source.subscribe(new WithLatestFromSubscriber(subscriber, this.observables, this.project)); |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class WithLatestFromSubscriber<T, R> extends OuterSubscriber<T, R> { |
| private values: any[]; |
| private toRespond: number[] = []; |
| |
| constructor(destination: Subscriber<R>, |
| private observables: Observable<any>[], |
| private project?: (...values: any[]) => Observable<R>) { |
| super(destination); |
| const len = observables.length; |
| this.values = new Array(len); |
| |
| for (let i = 0; i < len; i++) { |
| this.toRespond.push(i); |
| } |
| |
| for (let i = 0; i < len; i++) { |
| let observable = observables[i]; |
| this.add(subscribeToResult<T, R>(this, observable, <any>observable, i)); |
| } |
| } |
| |
| notifyNext(outerValue: T, innerValue: R, |
| outerIndex: number, innerIndex: number, |
| innerSub: InnerSubscriber<T, R>): void { |
| this.values[outerIndex] = innerValue; |
| const toRespond = this.toRespond; |
| if (toRespond.length > 0) { |
| const found = toRespond.indexOf(outerIndex); |
| if (found !== -1) { |
| toRespond.splice(found, 1); |
| } |
| } |
| } |
| |
| notifyComplete() { |
| // noop |
| } |
| |
| protected _next(value: T) { |
| if (this.toRespond.length === 0) { |
| const args = [value, ...this.values]; |
| if (this.project) { |
| this._tryProject(args); |
| } else { |
| this.destination.next(args); |
| } |
| } |
| } |
| |
| private _tryProject(args: any[]) { |
| let result: any; |
| try { |
| result = this.project.apply(this, args); |
| } catch (err) { |
| this.destination.error(err); |
| return; |
| } |
| this.destination.next(result); |
| } |
| } |