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.
|
*
|
* 
|
*
|
* 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();
|
}
|
}
|
}
|
}
|
