groupBy.js 8.36 KB
"use strict";
var __extends = (this && this.__extends) || function (d, b) {
    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
    function __() { this.constructor = d; }
    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var Subscriber_1 = require('../Subscriber');
var Subscription_1 = require('../Subscription');
var Observable_1 = require('../Observable');
var Subject_1 = require('../Subject');
var Map_1 = require('../util/Map');
var FastMap_1 = require('../util/FastMap');
/* tslint:disable: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.
 *
 * <img src="./img/groupBy.png" width="100%">
 *
 * @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 this.lift(new GroupByOperator(keySelector, elementSelector, durationSelector, subjectSelector));
}
exports.groupBy = groupBy;
var GroupByOperator = (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 = (function (_super) {
    __extends(GroupBySubscriber, _super);
    function GroupBySubscriber(destination, keySelector, elementSelector, durationSelector, subjectSelector) {
        _super.call(this, destination);
        this.keySelector = keySelector;
        this.elementSelector = elementSelector;
        this.durationSelector = durationSelector;
        this.subjectSelector = subjectSelector;
        this.groups = null;
        this.attemptedToUnsubscribe = false;
        this.count = 0;
    }
    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 = typeof key === 'string' ? new FastMap_1.FastMap() : new Map_1.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) {
            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 = (function (_super) {
    __extends(GroupDurationSubscriber, _super);
    function GroupDurationSubscriber(key, group, parent) {
        _super.call(this);
        this.key = key;
        this.group = group;
        this.parent = parent;
    }
    GroupDurationSubscriber.prototype._next = function (value) {
        this._complete();
    };
    GroupDurationSubscriber.prototype._error = function (err) {
        var group = this.group;
        if (!group.closed) {
            group.error(err);
        }
        this.parent.removeGroup(this.key);
    };
    GroupDurationSubscriber.prototype._complete = function () {
        var group = this.group;
        if (!group.closed) {
            group.complete();
        }
        this.parent.removeGroup(this.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 = (function (_super) {
    __extends(GroupedObservable, _super);
    function GroupedObservable(key, groupSubject, refCountSubscription) {
        _super.call(this);
        this.key = key;
        this.groupSubject = groupSubject;
        this.refCountSubscription = refCountSubscription;
    }
    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 = (function (_super) {
    __extends(InnerRefCountSubscription, _super);
    function InnerRefCountSubscription(parent) {
        _super.call(this);
        this.parent = parent;
        parent.count++;
    }
    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