@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
76 lines • 3.56 kB
JavaScript
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 __());
};
define(["require", "exports", '../Subscriber', '../util/tryCatch', '../util/errorObject'], function (require, exports, Subscriber_1, tryCatch_1, errorObject_1) {
"use strict";
/**
* Returns an Observable that emits all items emitted by the source Observable that are distinct by comparison from the previous item.
* If a comparator function is provided, then it will be called for each item to test for whether or not that value should be emitted.
* If a comparator function is not provided, an equality check is used by default.
* @param {function} [compare] optional comparison function called to test if an item is distinct from the previous item in the source.
* @return {Observable} an Observable that emits items from the source Observable with distinct values.
* @method distinctUntilChanged
* @owner Observable
*/
function distinctUntilChanged(compare, keySelector) {
return this.lift(new DistinctUntilChangedOperator(compare, keySelector));
}
exports.distinctUntilChanged = distinctUntilChanged;
var DistinctUntilChangedOperator = (function () {
function DistinctUntilChangedOperator(compare, keySelector) {
this.compare = compare;
this.keySelector = keySelector;
}
DistinctUntilChangedOperator.prototype.call = function (subscriber, source) {
return source._subscribe(new DistinctUntilChangedSubscriber(subscriber, this.compare, this.keySelector));
};
return DistinctUntilChangedOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var DistinctUntilChangedSubscriber = (function (_super) {
__extends(DistinctUntilChangedSubscriber, _super);
function DistinctUntilChangedSubscriber(destination, compare, keySelector) {
_super.call(this, destination);
this.keySelector = keySelector;
this.hasKey = false;
if (typeof compare === 'function') {
this.compare = compare;
}
}
DistinctUntilChangedSubscriber.prototype.compare = function (x, y) {
return x === y;
};
DistinctUntilChangedSubscriber.prototype._next = function (value) {
var keySelector = this.keySelector;
var key = value;
if (keySelector) {
key = tryCatch_1.tryCatch(this.keySelector)(value);
if (key === errorObject_1.errorObject) {
return this.destination.error(errorObject_1.errorObject.e);
}
}
var result = false;
if (this.hasKey) {
result = tryCatch_1.tryCatch(this.compare)(this.key, key);
if (result === errorObject_1.errorObject) {
return this.destination.error(errorObject_1.errorObject.e);
}
}
else {
this.hasKey = true;
}
if (Boolean(result) === false) {
this.key = key;
this.destination.next(value);
}
};
return DistinctUntilChangedSubscriber;
}(Subscriber_1.Subscriber));
});
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