257 lines
8.4 KiB
JavaScript
257 lines
8.4 KiB
JavaScript
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import { Subscriber } from '../Subscriber';
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import { Subscription } from '../Subscription';
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import { Observable } from '../Observable';
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import { Subject } from '../Subject';
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import { Map } from '../util/Map';
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import { FastMap } from '../util/FastMap';
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/* tslint:enable:max-line-length */
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/**
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* Groups the items emitted by an Observable according to a specified criterion,
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* and emits these grouped items as `GroupedObservables`, one
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* {@link GroupedObservable} per group.
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*
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* <img src="./img/groupBy.png" width="100%">
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*
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* @example <caption>Group objects by id and return as array</caption>
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* Observable.of<Obj>({id: 1, name: 'aze1'},
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* {id: 2, name: 'sf2'},
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* {id: 2, name: 'dg2'},
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* {id: 1, name: 'erg1'},
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* {id: 1, name: 'df1'},
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* {id: 2, name: 'sfqfb2'},
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* {id: 3, name: 'qfs3'},
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* {id: 2, name: 'qsgqsfg2'}
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* )
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* .groupBy(p => p.id)
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* .flatMap( (group$) => group$.reduce((acc, cur) => [...acc, cur], []))
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* .subscribe(p => console.log(p));
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*
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* // displays:
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* // [ { id: 1, name: 'aze1' },
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* // { id: 1, name: 'erg1' },
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* // { id: 1, name: 'df1' } ]
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* //
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* // [ { id: 2, name: 'sf2' },
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* // { id: 2, name: 'dg2' },
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* // { id: 2, name: 'sfqfb2' },
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* // { id: 2, name: 'qsgqsfg2' } ]
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* //
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* // [ { id: 3, name: 'qfs3' } ]
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*
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* @example <caption>Pivot data on the id field</caption>
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* Observable.of<Obj>({id: 1, name: 'aze1'},
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* {id: 2, name: 'sf2'},
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* {id: 2, name: 'dg2'},
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* {id: 1, name: 'erg1'},
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* {id: 1, name: 'df1'},
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* {id: 2, name: 'sfqfb2'},
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* {id: 3, name: 'qfs1'},
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* {id: 2, name: 'qsgqsfg2'}
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* )
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* .groupBy(p => p.id, p => p.name)
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* .flatMap( (group$) => group$.reduce((acc, cur) => [...acc, cur], ["" + group$.key]))
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* .map(arr => ({'id': parseInt(arr[0]), 'values': arr.slice(1)}))
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* .subscribe(p => console.log(p));
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*
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* // displays:
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* // { id: 1, values: [ 'aze1', 'erg1', 'df1' ] }
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* // { id: 2, values: [ 'sf2', 'dg2', 'sfqfb2', 'qsgqsfg2' ] }
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* // { id: 3, values: [ 'qfs1' ] }
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*
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* @param {function(value: T): K} keySelector A function that extracts the key
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* for each item.
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* @param {function(value: T): R} [elementSelector] A function that extracts the
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* return element for each item.
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* @param {function(grouped: GroupedObservable<K,R>): Observable<any>} [durationSelector]
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* A function that returns an Observable to determine how long each group should
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* exist.
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* @return {Observable<GroupedObservable<K,R>>} An Observable that emits
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* GroupedObservables, each of which corresponds to a unique key value and each
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* of which emits those items from the source Observable that share that key
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* value.
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* @method groupBy
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* @owner Observable
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*/
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export function groupBy(keySelector, elementSelector, durationSelector, subjectSelector) {
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return (source) => source.lift(new GroupByOperator(keySelector, elementSelector, durationSelector, subjectSelector));
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}
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class GroupByOperator {
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constructor(keySelector, elementSelector, durationSelector, subjectSelector) {
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this.keySelector = keySelector;
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this.elementSelector = elementSelector;
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this.durationSelector = durationSelector;
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this.subjectSelector = subjectSelector;
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}
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call(subscriber, source) {
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return source.subscribe(new GroupBySubscriber(subscriber, this.keySelector, this.elementSelector, this.durationSelector, this.subjectSelector));
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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 GroupBySubscriber extends Subscriber {
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constructor(destination, keySelector, elementSelector, durationSelector, subjectSelector) {
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super(destination);
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this.keySelector = keySelector;
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this.elementSelector = elementSelector;
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this.durationSelector = durationSelector;
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this.subjectSelector = subjectSelector;
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this.groups = null;
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this.attemptedToUnsubscribe = false;
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this.count = 0;
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}
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_next(value) {
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let key;
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try {
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key = this.keySelector(value);
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}
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catch (err) {
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this.error(err);
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return;
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}
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this._group(value, key);
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}
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_group(value, key) {
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let groups = this.groups;
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if (!groups) {
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groups = this.groups = typeof key === 'string' ? new FastMap() : new Map();
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}
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let group = groups.get(key);
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let element;
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if (this.elementSelector) {
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try {
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element = this.elementSelector(value);
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}
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catch (err) {
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this.error(err);
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}
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}
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else {
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element = value;
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}
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if (!group) {
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group = this.subjectSelector ? this.subjectSelector() : new Subject();
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groups.set(key, group);
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const groupedObservable = new GroupedObservable(key, group, this);
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this.destination.next(groupedObservable);
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if (this.durationSelector) {
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let duration;
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try {
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duration = this.durationSelector(new GroupedObservable(key, group));
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}
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catch (err) {
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this.error(err);
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return;
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}
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this.add(duration.subscribe(new GroupDurationSubscriber(key, group, this)));
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}
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}
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if (!group.closed) {
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group.next(element);
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}
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}
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_error(err) {
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const groups = this.groups;
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if (groups) {
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groups.forEach((group, key) => {
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group.error(err);
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});
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groups.clear();
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}
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this.destination.error(err);
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}
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_complete() {
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const groups = this.groups;
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if (groups) {
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groups.forEach((group, key) => {
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group.complete();
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});
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groups.clear();
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}
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this.destination.complete();
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}
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removeGroup(key) {
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this.groups.delete(key);
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}
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unsubscribe() {
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if (!this.closed) {
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this.attemptedToUnsubscribe = true;
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if (this.count === 0) {
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super.unsubscribe();
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}
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}
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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 GroupDurationSubscriber extends Subscriber {
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constructor(key, group, parent) {
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super(group);
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this.key = key;
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this.group = group;
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this.parent = parent;
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}
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_next(value) {
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this.complete();
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}
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/** @deprecated internal use only */ _unsubscribe() {
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const { parent, key } = this;
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this.key = this.parent = null;
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if (parent) {
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parent.removeGroup(key);
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}
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}
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}
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/**
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* An Observable representing values belonging to the same group represented by
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* a common key. The values emitted by a GroupedObservable come from the source
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* Observable. The common key is available as the field `key` on a
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* GroupedObservable instance.
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*
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* @class GroupedObservable<K, T>
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*/
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export class GroupedObservable extends Observable {
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constructor(key, groupSubject, refCountSubscription) {
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super();
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this.key = key;
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this.groupSubject = groupSubject;
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this.refCountSubscription = refCountSubscription;
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}
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/** @deprecated internal use only */ _subscribe(subscriber) {
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const subscription = new Subscription();
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const { refCountSubscription, groupSubject } = this;
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if (refCountSubscription && !refCountSubscription.closed) {
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subscription.add(new InnerRefCountSubscription(refCountSubscription));
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}
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subscription.add(groupSubject.subscribe(subscriber));
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return subscription;
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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 InnerRefCountSubscription extends Subscription {
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constructor(parent) {
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super();
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this.parent = parent;
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parent.count++;
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}
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unsubscribe() {
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const parent = this.parent;
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if (!parent.closed && !this.closed) {
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super.unsubscribe();
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parent.count -= 1;
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if (parent.count === 0 && parent.attemptedToUnsubscribe) {
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parent.unsubscribe();
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}
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}
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}
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}
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//# sourceMappingURL=groupBy.js.map
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