%PDF-
%PDF-
Mini Shell
Mini Shell
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();
}
}
}
}
Zerion Mini Shell 1.0