52 lines
2.3 KiB
JavaScript
52 lines
2.3 KiB
JavaScript
|
"use strict";
|
||
|
|
var distinct_1 = require('../operators/distinct');
|
||
|
|
/**
|
||
|
|
* Returns an Observable that emits all items emitted by the source Observable that are distinct by comparison from previous items.
|
||
|
|
*
|
||
|
|
* If a keySelector function is provided, then it will project each value from the source observable into a new value that it will
|
||
|
|
* check for equality with previously projected values. If a keySelector function is not provided, it will use each value from the
|
||
|
|
* source observable directly with an equality check against previous values.
|
||
|
|
*
|
||
|
|
* In JavaScript runtimes that support `Set`, this operator will use a `Set` to improve performance of the distinct value checking.
|
||
|
|
*
|
||
|
|
* In other runtimes, this operator will use a minimal implementation of `Set` that relies on an `Array` and `indexOf` under the
|
||
|
|
* hood, so performance will degrade as more values are checked for distinction. Even in newer browsers, a long-running `distinct`
|
||
|
|
* use might result in memory leaks. To help alleviate this in some scenarios, an optional `flushes` parameter is also provided so
|
||
|
|
* that the internal `Set` can be "flushed", basically clearing it of values.
|
||
|
|
*
|
||
|
|
* @example <caption>A simple example with numbers</caption>
|
||
|
|
* Observable.of(1, 1, 2, 2, 2, 1, 2, 3, 4, 3, 2, 1)
|
||
|
|
* .distinct()
|
||
|
|
* .subscribe(x => console.log(x)); // 1, 2, 3, 4
|
||
|
|
*
|
||
|
|
* @example <caption>An example using a keySelector function</caption>
|
||
|
|
* interface Person {
|
||
|
|
* age: number,
|
||
|
|
* name: string
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* Observable.of<Person>(
|
||
|
|
* { age: 4, name: 'Foo'},
|
||
|
|
* { age: 7, name: 'Bar'},
|
||
|
|
* { age: 5, name: 'Foo'})
|
||
|
|
* .distinct((p: Person) => p.name)
|
||
|
|
* .subscribe(x => console.log(x));
|
||
|
|
*
|
||
|
|
* // displays:
|
||
|
|
* // { age: 4, name: 'Foo' }
|
||
|
|
* // { age: 7, name: 'Bar' }
|
||
|
|
*
|
||
|
|
* @see {@link distinctUntilChanged}
|
||
|
|
* @see {@link distinctUntilKeyChanged}
|
||
|
|
*
|
||
|
|
* @param {function} [keySelector] Optional function to select which value you want to check as distinct.
|
||
|
|
* @param {Observable} [flushes] Optional Observable for flushing the internal HashSet of the operator.
|
||
|
|
* @return {Observable} An Observable that emits items from the source Observable with distinct values.
|
||
|
|
* @method distinct
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
function distinct(keySelector, flushes) {
|
||
|
|
return distinct_1.distinct(keySelector, flushes)(this);
|
||
|
|
}
|
||
|
|
exports.distinct = distinct;
|
||
|
|
//# sourceMappingURL=distinct.js.map
|