distinct.d.ts
2.33 KB
import { Observable } from '../Observable';
import { Subscriber } from '../Subscriber';
import { OuterSubscriber } from '../OuterSubscriber';
import { InnerSubscriber } from '../InnerSubscriber';
/**
* 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.
* @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
*/
export declare function distinct<T, K>(this: Observable<T>, keySelector?: (value: T) => K, flushes?: Observable<any>): Observable<T>;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
export declare class DistinctSubscriber<T, K> extends OuterSubscriber<T, T> {
private keySelector;
private values;
constructor(destination: Subscriber<T>, keySelector: (value: T) => K, flushes: Observable<any>);
notifyNext(outerValue: T, innerValue: T, outerIndex: number, innerIndex: number, innerSub: InnerSubscriber<T, T>): void;
notifyError(error: any, innerSub: InnerSubscriber<T, T>): void;
protected _next(value: T): void;
private _useKeySelector(value);
private _finalizeNext(key, value);
}