rxjs
Version:
Reactive Extensions for modern JavaScript
60 lines (59 loc) • 2.35 kB
JavaScript
/** PURE_IMPORTS_START tslib,_Subscriber,_util_tryCatch,_util_errorObject PURE_IMPORTS_END */
import * as tslib_1 from "tslib";
import { Subscriber } from '../Subscriber';
import { tryCatch } from '../util/tryCatch';
import { errorObject } from '../util/errorObject';
export function distinctUntilChanged(compare, keySelector) {
return function (source) { return source.lift(new DistinctUntilChangedOperator(compare, keySelector)); };
}
var DistinctUntilChangedOperator = /*@__PURE__*/ (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;
}());
var DistinctUntilChangedSubscriber = /*@__PURE__*/ (function (_super) {
tslib_1.__extends(DistinctUntilChangedSubscriber, _super);
function DistinctUntilChangedSubscriber(destination, compare, keySelector) {
var _this = _super.call(this, destination) || this;
_this.keySelector = keySelector;
_this.hasKey = false;
if (typeof compare === 'function') {
_this.compare = compare;
}
return _this;
}
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(this.keySelector)(value);
if (key === errorObject) {
return this.destination.error(errorObject.e);
}
}
var result = false;
if (this.hasKey) {
result = tryCatch(this.compare)(this.key, key);
if (result === errorObject) {
return this.destination.error(errorObject.e);
}
}
else {
this.hasKey = true;
}
if (Boolean(result) === false) {
this.key = key;
this.destination.next(value);
}
};
return DistinctUntilChangedSubscriber;
}(Subscriber));
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