255 lines
7.4 KiB
JavaScript
255 lines
7.4 KiB
JavaScript
import { ArrayObservable } from '../observable/ArrayObservable';
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import { isArray } from '../util/isArray';
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import { Subscriber } from '../Subscriber';
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import { OuterSubscriber } from '../OuterSubscriber';
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import { subscribeToResult } from '../util/subscribeToResult';
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import { iterator as Symbol_iterator } from '../symbol/iterator';
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/* tslint:enable:max-line-length */
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/**
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* @param observables
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* @return {Observable<R>}
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* @method zip
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* @owner Observable
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*/
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export function zip(...observables) {
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return function zipOperatorFunction(source) {
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return source.lift.call(zipStatic(source, ...observables));
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};
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}
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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 calculated from the values, in order, of each
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* of its input Observables.
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*
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* If the latest parameter is a function, this function is used to compute the created value from the input values.
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* Otherwise, an array of the input values is returned.
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*
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* @example <caption>Combine age and name from different sources</caption>
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*
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* let age$ = Observable.of<number>(27, 25, 29);
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* let name$ = Observable.of<string>('Foo', 'Bar', 'Beer');
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* let isDev$ = Observable.of<boolean>(true, true, false);
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*
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* Observable
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* .zip(age$,
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* name$,
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* isDev$,
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* (age: number, name: string, isDev: boolean) => ({ age, name, isDev }))
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* .subscribe(x => console.log(x));
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*
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* // outputs
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* // { age: 27, name: 'Foo', isDev: true }
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* // { age: 25, name: 'Bar', isDev: true }
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* // { age: 29, name: 'Beer', isDev: false }
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*
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* @param observables
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* @return {Observable<R>}
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* @static true
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* @name zip
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* @owner Observable
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*/
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export function zipStatic(...observables) {
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const project = observables[observables.length - 1];
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if (typeof project === 'function') {
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observables.pop();
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}
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return new ArrayObservable(observables).lift(new ZipOperator(project));
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}
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export class ZipOperator {
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constructor(project) {
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this.project = project;
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}
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call(subscriber, source) {
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return source.subscribe(new ZipSubscriber(subscriber, this.project));
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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export class ZipSubscriber extends Subscriber {
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constructor(destination, project, values = Object.create(null)) {
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super(destination);
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this.iterators = [];
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this.active = 0;
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this.project = (typeof project === 'function') ? project : null;
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this.values = values;
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}
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_next(value) {
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const iterators = this.iterators;
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if (isArray(value)) {
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iterators.push(new StaticArrayIterator(value));
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}
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else if (typeof value[Symbol_iterator] === 'function') {
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iterators.push(new StaticIterator(value[Symbol_iterator]()));
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}
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else {
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iterators.push(new ZipBufferIterator(this.destination, this, value));
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}
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}
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_complete() {
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const iterators = this.iterators;
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const len = iterators.length;
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if (len === 0) {
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this.destination.complete();
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return;
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}
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this.active = len;
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for (let i = 0; i < len; i++) {
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let iterator = iterators[i];
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if (iterator.stillUnsubscribed) {
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this.add(iterator.subscribe(iterator, i));
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}
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else {
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this.active--; // not an observable
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}
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}
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}
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notifyInactive() {
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this.active--;
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if (this.active === 0) {
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this.destination.complete();
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}
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}
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checkIterators() {
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const iterators = this.iterators;
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const len = iterators.length;
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const destination = this.destination;
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// abort if not all of them have values
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for (let i = 0; i < len; i++) {
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let iterator = iterators[i];
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if (typeof iterator.hasValue === 'function' && !iterator.hasValue()) {
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return;
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}
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}
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let shouldComplete = false;
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const args = [];
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for (let i = 0; i < len; i++) {
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let iterator = iterators[i];
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let result = iterator.next();
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// check to see if it's completed now that you've gotten
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// the next value.
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if (iterator.hasCompleted()) {
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shouldComplete = true;
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}
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if (result.done) {
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destination.complete();
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return;
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}
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args.push(result.value);
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}
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if (this.project) {
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this._tryProject(args);
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}
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else {
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destination.next(args);
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}
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if (shouldComplete) {
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destination.complete();
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}
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}
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_tryProject(args) {
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let result;
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try {
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result = this.project.apply(this, args);
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}
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catch (err) {
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this.destination.error(err);
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return;
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}
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this.destination.next(result);
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}
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}
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class StaticIterator {
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constructor(iterator) {
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this.iterator = iterator;
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this.nextResult = iterator.next();
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}
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hasValue() {
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return true;
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}
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next() {
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const result = this.nextResult;
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this.nextResult = this.iterator.next();
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return result;
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}
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hasCompleted() {
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const nextResult = this.nextResult;
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return nextResult && nextResult.done;
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}
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}
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class StaticArrayIterator {
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constructor(array) {
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this.array = array;
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this.index = 0;
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this.length = 0;
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this.length = array.length;
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}
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[Symbol_iterator]() {
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return this;
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}
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next(value) {
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const i = this.index++;
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const array = this.array;
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return i < this.length ? { value: array[i], done: false } : { value: null, done: true };
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}
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hasValue() {
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return this.array.length > this.index;
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}
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hasCompleted() {
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return this.array.length === this.index;
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class ZipBufferIterator extends OuterSubscriber {
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constructor(destination, parent, observable) {
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super(destination);
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this.parent = parent;
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this.observable = observable;
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this.stillUnsubscribed = true;
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this.buffer = [];
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this.isComplete = false;
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}
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[Symbol_iterator]() {
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return this;
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}
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// NOTE: there is actually a name collision here with Subscriber.next and Iterator.next
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// this is legit because `next()` will never be called by a subscription in this case.
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next() {
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const buffer = this.buffer;
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if (buffer.length === 0 && this.isComplete) {
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return { value: null, done: true };
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}
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else {
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return { value: buffer.shift(), done: false };
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}
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}
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hasValue() {
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return this.buffer.length > 0;
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}
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hasCompleted() {
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return this.buffer.length === 0 && this.isComplete;
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}
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notifyComplete() {
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if (this.buffer.length > 0) {
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this.isComplete = true;
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this.parent.notifyInactive();
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}
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else {
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this.destination.complete();
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}
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}
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notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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this.buffer.push(innerValue);
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this.parent.checkIterators();
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}
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subscribe(value, index) {
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return subscribeToResult(this, this.observable, this, index);
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}
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}
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//# sourceMappingURL=zip.js.map
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