work.suroh.tk/node_modules/rxjs/_esm5/operators/distinctUntilChanged.js

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2019-12-02 12:22:45 +00:00
/** PURE_IMPORTS_START .._Subscriber,.._util_tryCatch,.._util_errorObject PURE_IMPORTS_END */
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 __());
};
import { Subscriber } from '../Subscriber';
import { tryCatch } from '../util/tryCatch';
import { errorObject } from '../util/errorObject';
/* tslint:enable:max-line-length */
/**
* 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.
*
* @example <caption>A simple example with numbers</caption>
* Observable.of(1, 1, 2, 2, 2, 1, 1, 2, 3, 3, 4)
* .distinctUntilChanged()
* .subscribe(x => console.log(x)); // 1, 2, 1, 2, 3, 4
*
* @example <caption>An example using a compare function</caption>
* interface Person {
* age: number,
* name: string
* }
*
* Observable.of<Person>(
* { age: 4, name: 'Foo'},
* { age: 7, name: 'Bar'},
* { age: 5, name: 'Foo'})
* { age: 6, name: 'Foo'})
* .distinctUntilChanged((p: Person, q: Person) => p.name === q.name)
* .subscribe(x => console.log(x));
*
* // displays:
* // { age: 4, name: 'Foo' }
* // { age: 7, name: 'Bar' }
* // { age: 5, name: 'Foo' }
*
* @see {@link distinct}
* @see {@link distinctUntilKeyChanged}
*
* @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
*/
export function distinctUntilChanged(compare, keySelector) {
return function (source) { return source.lift(new DistinctUntilChangedOperator(compare, keySelector)); };
}
var DistinctUntilChangedOperator = /*@__PURE__*/ (/*@__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;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var DistinctUntilChangedSubscriber = /*@__PURE__*/ (/*@__PURE__*/ 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(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));
//# sourceMappingURL=distinctUntilChanged.js.map