@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
313 lines • 11.2 kB
JavaScript
"use strict";
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
}
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
var Subscriber_1 = require("../Subscriber");
var Subscription_1 = require("../Subscription");
var Observable_1 = require("../Observable");
var Subject_1 = require("../Subject");
/* 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
*/
function groupBy(keySelector, elementSelector, durationSelector, subjectSelector) {
return function (source) {
return source.lift(new GroupByOperator(keySelector, elementSelector, durationSelector, subjectSelector));
};
}
exports.groupBy = groupBy;
var GroupByOperator = /** @class */ (function () {
function GroupByOperator(keySelector, elementSelector, durationSelector, subjectSelector) {
this.keySelector = keySelector;
this.elementSelector = elementSelector;
this.durationSelector = durationSelector;
this.subjectSelector = subjectSelector;
}
GroupByOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new GroupBySubscriber(subscriber, this.keySelector, this.elementSelector, this.durationSelector, this.subjectSelector));
};
return GroupByOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var GroupBySubscriber = /** @class */ (function (_super) {
__extends(GroupBySubscriber, _super);
function GroupBySubscriber(destination, keySelector, elementSelector, durationSelector, subjectSelector) {
var _this = _super.call(this, destination) || this;
_this.keySelector = keySelector;
_this.elementSelector = elementSelector;
_this.durationSelector = durationSelector;
_this.subjectSelector = subjectSelector;
_this.groups = null;
_this.attemptedToUnsubscribe = false;
_this.count = 0;
return _this;
}
GroupBySubscriber.prototype._next = function (value) {
var key;
try {
key = this.keySelector(value);
}
catch (err) {
this.error(err);
return;
}
this._group(value, key);
};
GroupBySubscriber.prototype._group = function (value, key) {
var groups = this.groups;
if (!groups) {
groups = this.groups = new Map();
}
var group = groups.get(key);
var element;
if (this.elementSelector) {
try {
element = this.elementSelector(value);
}
catch (err) {
this.error(err);
}
}
else {
element = value;
}
if (!group) {
group = (this.subjectSelector ? this.subjectSelector() : new Subject_1.Subject());
groups.set(key, group);
var groupedObservable = new GroupedObservable(key, group, this);
this.destination.next(groupedObservable);
if (this.durationSelector) {
var duration = void 0;
try {
duration = this.durationSelector(new GroupedObservable(key, group));
}
catch (err) {
this.error(err);
return;
}
this.add(duration.subscribe(new GroupDurationSubscriber(key, group, this)));
}
}
if (!group.closed) {
group.next(element);
}
};
GroupBySubscriber.prototype._error = function (err) {
var groups = this.groups;
if (groups) {
groups.forEach(function (group, key) {
group.error(err);
});
groups.clear();
}
this.destination.error(err);
};
GroupBySubscriber.prototype._complete = function () {
var groups = this.groups;
if (groups) {
groups.forEach(function (group, key) {
group.complete();
});
groups.clear();
}
this.destination.complete();
};
GroupBySubscriber.prototype.removeGroup = function (key) {
this.groups.delete(key);
};
GroupBySubscriber.prototype.unsubscribe = function () {
if (!this.closed) {
this.attemptedToUnsubscribe = true;
if (this.count === 0) {
_super.prototype.unsubscribe.call(this);
}
}
};
return GroupBySubscriber;
}(Subscriber_1.Subscriber));
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var GroupDurationSubscriber = /** @class */ (function (_super) {
__extends(GroupDurationSubscriber, _super);
function GroupDurationSubscriber(key, group, parent) {
var _this = _super.call(this, group) || this;
_this.key = key;
_this.group = group;
_this.parent = parent;
return _this;
}
GroupDurationSubscriber.prototype._next = function (value) {
this.complete();
};
/** @deprecated This is an internal implementation detail, do not use. */
GroupDurationSubscriber.prototype._unsubscribe = function () {
var _a = this, parent = _a.parent, key = _a.key;
this.key = this.parent = null;
if (parent) {
parent.removeGroup(key);
}
};
return GroupDurationSubscriber;
}(Subscriber_1.Subscriber));
/**
* 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>
*/
var GroupedObservable = /** @class */ (function (_super) {
__extends(GroupedObservable, _super);
/** @deprecated Do not construct this type. Internal use only */
function GroupedObservable(key, groupSubject, refCountSubscription) {
var _this = _super.call(this) || this;
_this.key = key;
_this.groupSubject = groupSubject;
_this.refCountSubscription = refCountSubscription;
return _this;
}
/** @deprecated This is an internal implementation detail, do not use. */
GroupedObservable.prototype._subscribe = function (subscriber) {
var subscription = new Subscription_1.Subscription();
var _a = this, refCountSubscription = _a.refCountSubscription, groupSubject = _a.groupSubject;
if (refCountSubscription && !refCountSubscription.closed) {
subscription.add(new InnerRefCountSubscription(refCountSubscription));
}
subscription.add(groupSubject.subscribe(subscriber));
return subscription;
};
return GroupedObservable;
}(Observable_1.Observable));
exports.GroupedObservable = GroupedObservable;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var InnerRefCountSubscription = /** @class */ (function (_super) {
__extends(InnerRefCountSubscription, _super);
function InnerRefCountSubscription(parent) {
var _this = _super.call(this) || this;
_this.parent = parent;
parent.count++;
return _this;
}
InnerRefCountSubscription.prototype.unsubscribe = function () {
var parent = this.parent;
if (!parent.closed && !this.closed) {
_super.prototype.unsubscribe.call(this);
parent.count -= 1;
if (parent.count === 0 && parent.attemptedToUnsubscribe) {
parent.unsubscribe();
}
}
};
return InnerRefCountSubscription;
}(Subscription_1.Subscription));
//# sourceMappingURL=groupBy.js.map