| import { Subscriber } from '../Subscriber'; |
| import { Subscription } from '../Subscription'; |
| import { Observable } from '../Observable'; |
| import { Operator } from '../Operator'; |
| import { Subject } from '../Subject'; |
| import { OperatorFunction } from '../types'; |
| |
| /* tslint:disable:max-line-length */ |
| export function groupBy<T, K>(keySelector: (value: T) => K): OperatorFunction<T, GroupedObservable<K, T>>; |
| export function groupBy<T, K>(keySelector: (value: T) => K, elementSelector: void, durationSelector: (grouped: GroupedObservable<K, T>) => Observable<any>): OperatorFunction<T, GroupedObservable<K, T>>; |
| export function groupBy<T, K, R>(keySelector: (value: T) => K, elementSelector?: (value: T) => R, durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>): OperatorFunction<T, GroupedObservable<K, R>>; |
| export function groupBy<T, K, R>(keySelector: (value: T) => K, elementSelector?: (value: T) => R, durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>, subjectSelector?: () => Subject<R>): OperatorFunction<T, GroupedObservable<K, R>>; |
| /* tslint:enable:max-line-length */ |
| |
| /** |
| * Groups the items emitted by an Observable according to a specified criterion, |
| * and emits these grouped items as `GroupedObservables`, one |
| * {@link GroupedObservable} per group. |
| * |
| * ![](groupBy.png) |
| * |
| * When the Observable emits an item, a key is computed for this item with the keySelector function. |
| * |
| * If a {@link GroupedObservable} for this key exists, this {@link GroupedObservable} emits. Elsewhere, a new |
| * {@link GroupedObservable} for this key is created and emits. |
| * |
| * A {@link GroupedObservable} represents values belonging to the same group represented by a common key. The common |
| * key is available as the key field of a {@link GroupedObservable} instance. |
| * |
| * The elements emitted by {@link GroupedObservable}s are by default the items emitted by the Observable, or elements |
| * returned by the elementSelector function. |
| * |
| * ## Examples |
| * |
| * ### Group objects by id and return as array |
| * |
| * ```ts |
| * import { of } from 'rxjs'; |
| * import { mergeMap, groupBy, reduce } from 'rxjs/operators'; |
| * |
| * of( |
| * {id: 1, name: 'JavaScript'}, |
| * {id: 2, name: 'Parcel'}, |
| * {id: 2, name: 'webpack'}, |
| * {id: 1, name: 'TypeScript'}, |
| * {id: 3, name: 'TSLint'} |
| * ).pipe( |
| * groupBy(p => p.id), |
| * mergeMap((group$) => group$.pipe(reduce((acc, cur) => [...acc, cur], []))), |
| * ) |
| * .subscribe(p => console.log(p)); |
| * |
| * // displays: |
| * // [ { id: 1, name: 'JavaScript'}, |
| * // { id: 1, name: 'TypeScript'} ] |
| * // |
| * // [ { id: 2, name: 'Parcel'}, |
| * // { id: 2, name: 'webpack'} ] |
| * // |
| * // [ { id: 3, name: 'TSLint'} ] |
| * ``` |
| * |
| * ### Pivot data on the id field |
| * |
| * ```ts |
| * import { of } from 'rxjs'; |
| * import { groupBy, map, mergeMap, reduce } from 'rxjs/operators'; |
| * |
| * of( |
| * { id: 1, name: 'JavaScript' }, |
| * { id: 2, name: 'Parcel' }, |
| * { id: 2, name: 'webpack' }, |
| * { id: 1, name: 'TypeScript' }, |
| * { id: 3, name: 'TSLint' } |
| * ) |
| * .pipe( |
| * groupBy(p => p.id, p => p.name), |
| * mergeMap(group$ => |
| * group$.pipe(reduce((acc, cur) => [...acc, cur], [`${group$.key}`])) |
| * ), |
| * map(arr => ({ id: parseInt(arr[0], 10), values: arr.slice(1) })) |
| * ) |
| * .subscribe(p => console.log(p)); |
| * |
| * // displays: |
| * // { id: 1, values: [ 'JavaScript', 'TypeScript' ] } |
| * // { id: 2, values: [ 'Parcel', 'webpack' ] } |
| * // { id: 3, values: [ 'TSLint' ] } |
| * ``` |
| * |
| * @param {function(value: T): K} keySelector A function that extracts the key |
| * for each item. |
| * @param {function(value: T): R} [elementSelector] A function that extracts the |
| * return element for each item. |
| * @param {function(grouped: GroupedObservable<K,R>): Observable<any>} [durationSelector] |
| * A function that returns an Observable to determine how long each group should |
| * exist. |
| * @return {Observable<GroupedObservable<K,R>>} An Observable that emits |
| * GroupedObservables, each of which corresponds to a unique key value and each |
| * of which emits those items from the source Observable that share that key |
| * value. |
| * @method groupBy |
| * @owner Observable |
| */ |
| export function groupBy<T, K, R>(keySelector: (value: T) => K, |
| elementSelector?: ((value: T) => R) | void, |
| durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>, |
| subjectSelector?: () => Subject<R>): OperatorFunction<T, GroupedObservable<K, R>> { |
| return (source: Observable<T>) => |
| source.lift(new GroupByOperator(keySelector, elementSelector, durationSelector, subjectSelector)); |
| } |
| |
| export interface RefCountSubscription { |
| count: number; |
| unsubscribe: () => void; |
| closed: boolean; |
| attemptedToUnsubscribe: boolean; |
| } |
| |
| class GroupByOperator<T, K, R> implements Operator<T, GroupedObservable<K, R>> { |
| constructor(private keySelector: (value: T) => K, |
| private elementSelector?: ((value: T) => R) | void, |
| private durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>, |
| private subjectSelector?: () => Subject<R>) { |
| } |
| |
| call(subscriber: Subscriber<GroupedObservable<K, R>>, source: any): any { |
| return source.subscribe(new GroupBySubscriber( |
| subscriber, this.keySelector, this.elementSelector, this.durationSelector, this.subjectSelector |
| )); |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class GroupBySubscriber<T, K, R> extends Subscriber<T> implements RefCountSubscription { |
| private groups: Map<K, Subject<T | R>> = null; |
| public attemptedToUnsubscribe: boolean = false; |
| public count: number = 0; |
| |
| constructor(destination: Subscriber<GroupedObservable<K, R>>, |
| private keySelector: (value: T) => K, |
| private elementSelector?: ((value: T) => R) | void, |
| private durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>, |
| private subjectSelector?: () => Subject<R>) { |
| super(destination); |
| } |
| |
| protected _next(value: T): void { |
| let key: K; |
| try { |
| key = this.keySelector(value); |
| } catch (err) { |
| this.error(err); |
| return; |
| } |
| |
| this._group(value, key); |
| } |
| |
| private _group(value: T, key: K) { |
| let groups = this.groups; |
| |
| if (!groups) { |
| groups = this.groups = new Map<K, Subject<T | R>>(); |
| } |
| |
| let group = groups.get(key); |
| |
| let element: R; |
| if (this.elementSelector) { |
| try { |
| element = this.elementSelector(value); |
| } catch (err) { |
| this.error(err); |
| } |
| } else { |
| element = <any>value; |
| } |
| |
| if (!group) { |
| group = (this.subjectSelector ? this.subjectSelector() : new Subject<R>()) as Subject<T | R>; |
| groups.set(key, group); |
| const groupedObservable = new GroupedObservable(key, group, this); |
| this.destination.next(groupedObservable); |
| if (this.durationSelector) { |
| let duration: any; |
| try { |
| duration = this.durationSelector(new GroupedObservable<K, R>(key, <Subject<R>>group)); |
| } catch (err) { |
| this.error(err); |
| return; |
| } |
| this.add(duration.subscribe(new GroupDurationSubscriber(key, group, this))); |
| } |
| } |
| |
| if (!group.closed) { |
| group.next(element); |
| } |
| } |
| |
| protected _error(err: any): void { |
| const groups = this.groups; |
| if (groups) { |
| groups.forEach((group, key) => { |
| group.error(err); |
| }); |
| |
| groups.clear(); |
| } |
| this.destination.error(err); |
| } |
| |
| protected _complete(): void { |
| const groups = this.groups; |
| if (groups) { |
| groups.forEach((group, key) => { |
| group.complete(); |
| }); |
| |
| groups.clear(); |
| } |
| this.destination.complete(); |
| } |
| |
| removeGroup(key: K): void { |
| this.groups.delete(key); |
| } |
| |
| unsubscribe() { |
| if (!this.closed) { |
| this.attemptedToUnsubscribe = true; |
| if (this.count === 0) { |
| super.unsubscribe(); |
| } |
| } |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class GroupDurationSubscriber<K, T> extends Subscriber<T> { |
| constructor(private key: K, |
| private group: Subject<T>, |
| private parent: GroupBySubscriber<any, K, T | any>) { |
| super(group); |
| } |
| |
| protected _next(value: T): void { |
| this.complete(); |
| } |
| |
| /** @deprecated This is an internal implementation detail, do not use. */ |
| _unsubscribe() { |
| const { parent, key } = this; |
| this.key = this.parent = null; |
| if (parent) { |
| parent.removeGroup(key); |
| } |
| } |
| } |
| |
| /** |
| * An Observable representing values belonging to the same group represented by |
| * a common key. The values emitted by a GroupedObservable come from the source |
| * Observable. The common key is available as the field `key` on a |
| * GroupedObservable instance. |
| * |
| * @class GroupedObservable<K, T> |
| */ |
| export class GroupedObservable<K, T> extends Observable<T> { |
| /** @deprecated Do not construct this type. Internal use only */ |
| constructor(public key: K, |
| private groupSubject: Subject<T>, |
| private refCountSubscription?: RefCountSubscription) { |
| super(); |
| } |
| |
| /** @deprecated This is an internal implementation detail, do not use. */ |
| _subscribe(subscriber: Subscriber<T>) { |
| const subscription = new Subscription(); |
| const { refCountSubscription, groupSubject } = this; |
| if (refCountSubscription && !refCountSubscription.closed) { |
| subscription.add(new InnerRefCountSubscription(refCountSubscription)); |
| } |
| subscription.add(groupSubject.subscribe(subscriber)); |
| return subscription; |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class InnerRefCountSubscription extends Subscription { |
| constructor(private parent: RefCountSubscription) { |
| super(); |
| parent.count++; |
| } |
| |
| unsubscribe() { |
| const parent = this.parent; |
| if (!parent.closed && !this.closed) { |
| super.unsubscribe(); |
| parent.count -= 1; |
| if (parent.count === 0 && parent.attemptedToUnsubscribe) { |
| parent.unsubscribe(); |
| } |
| } |
| } |
| } |