es6/operator/zip.js

import { ArrayObservable } from '../observable/ArrayObservable';
import { isArray } from '../util/isArray';
import { Subscriber } from '../Subscriber';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
import { iterator as Symbol_iterator } from '../symbol/iterator';
/* tslint:enable:max-line-length */
/**
 * @param observables
 * @return {Observable<R>}
 * @method zip
 * @owner Observable
 */
export function zipProto(...observables) {
    return this.lift.call(zipStatic(this, ...observables));
}
/* tslint:enable:max-line-length */
/**
 * 将多个 Observable 组合以创建一个 Observable，该 Observable 的值是由所有输入 Observables 的值按顺序计算而来的。
 *
 * 如果最后一个参数是函数, 这个函数被用来计算最终发出的值.否则, 返回一个顺序包含所有输入值的数组.
 *
 * @example <caption>从不同的源头结合年龄和名称</caption>
 *
 * let age$ = Observable.of<number>(27, 25, 29);
 * let name$ = Observable.of<string>('Foo', 'Bar', 'Beer');
 * let isDev$ = Observable.of<boolean>(true, true, false);
 *
 * Observable
 *     .zip(age$,
 *          name$,
 *          isDev$,
 *          (age: number, name: string, isDev: boolean) => ({ age, name, isDev }))
 *     .subscribe(x => console.log(x));
 *
 * // 输出：
 * // { age: 27, name: 'Foo', isDev: true }
 * // { age: 25, name: 'Bar', isDev: true }
 * // { age: 29, name: 'Beer', isDev: false }
 *
 * @param observables
 * @return {Observable<R>}
 * @static true
 * @name zip
 * @owner Observable
 */
export function zipStatic(...observables) {
    const project = observables[observables.length - 1];
    if (typeof project === 'function') {
        observables.pop();
    }
    return new ArrayObservable(observables).lift(new ZipOperator(project));
}
export class ZipOperator {
    constructor(project) {
        this.project = project;
    }
    call(subscriber, source) {
        return source.subscribe(new ZipSubscriber(subscriber, this.project));
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
export class ZipSubscriber extends Subscriber {
    constructor(destination, project, values = Object.create(null)) {
        super(destination);
        this.iterators = [];
        this.active = 0;
        this.project = (typeof project === 'function') ? project : null;
        this.values = values;
    }
    _next(value) {
        const iterators = this.iterators;
        if (isArray(value)) {
            iterators.push(new StaticArrayIterator(value));
        }
        else if (typeof value[Symbol_iterator] === 'function') {
            iterators.push(new StaticIterator(value[Symbol_iterator]()));
        }
        else {
            iterators.push(new ZipBufferIterator(this.destination, this, value));
        }
    }
    _complete() {
        const iterators = this.iterators;
        const len = iterators.length;
        if (len === 0) {
            this.destination.complete();
            return;
        }
        this.active = len;
        for (let i = 0; i < len; i++) {
            let iterator = iterators[i];
            if (iterator.stillUnsubscribed) {
                this.add(iterator.subscribe(iterator, i));
            }
            else {
                this.active--; // not an observable
            }
        }
    }
    notifyInactive() {
        this.active--;
        if (this.active === 0) {
            this.destination.complete();
        }
    }
    checkIterators() {
        const iterators = this.iterators;
        const len = iterators.length;
        const destination = this.destination;
        // abort if not all of them have values
        for (let i = 0; i < len; i++) {
            let iterator = iterators[i];
            if (typeof iterator.hasValue === 'function' && !iterator.hasValue()) {
                return;
            }
        }
        let shouldComplete = false;
        const args = [];
        for (let i = 0; i < len; i++) {
            let iterator = iterators[i];
            let result = iterator.next();
            // check to see if it's completed now that you've gotten
            // the next value.
            if (iterator.hasCompleted()) {
                shouldComplete = true;
            }
            if (result.done) {
                destination.complete();
                return;
            }
            args.push(result.value);
        }
        if (this.project) {
            this._tryProject(args);
        }
        else {
            destination.next(args);
        }
        if (shouldComplete) {
            destination.complete();
        }
    }
    _tryProject(args) {
        let result;
        try {
            result = this.project.apply(this, args);
        }
        catch (err) {
            this.destination.error(err);
            return;
        }
        this.destination.next(result);
    }
}
class StaticIterator {
    constructor(iterator) {
        this.iterator = iterator;
        this.nextResult = iterator.next();
    }
    hasValue() {
        return true;
    }
    next() {
        const result = this.nextResult;
        this.nextResult = this.iterator.next();
        return result;
    }
    hasCompleted() {
        const nextResult = this.nextResult;
        return nextResult && nextResult.done;
    }
}
class StaticArrayIterator {
    constructor(array) {
        this.array = array;
        this.index = 0;
        this.length = 0;
        this.length = array.length;
    }
    [Symbol_iterator]() {
        return this;
    }
    next(value) {
        const i = this.index++;
        const array = this.array;
        return i < this.length ? { value: array[i], done: false } : { value: null, done: true };
    }
    hasValue() {
        return this.array.length > this.index;
    }
    hasCompleted() {
        return this.array.length === this.index;
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
class ZipBufferIterator extends OuterSubscriber {
    constructor(destination, parent, observable) {
        super(destination);
        this.parent = parent;
        this.observable = observable;
        this.stillUnsubscribed = true;
        this.buffer = [];
        this.isComplete = false;
    }
    [Symbol_iterator]() {
        return this;
    }
    // NOTE: there is actually a name collision here with Subscriber.next and Iterator.next
    //    this is legit because `next()` will never be called by a subscription in this case.
    next() {
        const buffer = this.buffer;
        if (buffer.length === 0 && this.isComplete) {
            return { value: null, done: true };
        }
        else {
            return { value: buffer.shift(), done: false };
        }
    }
    hasValue() {
        return this.buffer.length > 0;
    }
    hasCompleted() {
        return this.buffer.length === 0 && this.isComplete;
    }
    notifyComplete() {
        if (this.buffer.length > 0) {
            this.isComplete = true;
            this.parent.notifyInactive();
        }
        else {
            this.destination.complete();
        }
    }
    notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
        this.buffer.push(innerValue);
        this.parent.checkIterators();
    }
    subscribe(value, index) {
        return subscribeToResult(this, this.observable, this, index);
    }
}
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