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import { Observable } from '../Observable';
import { last as higherOrder } from '../operators/last';
/* tslint:disable:max-line-length */
export function last<T, S extends T>(this: Observable<T>,
predicate: (value: T, index: number, source: Observable<T>) => value is S): Observable<S>;
export function last<T, S extends T, R>(this: Observable<T>,
predicate: (value: T | S, index: number, source: Observable<T>) => value is S,
resultSelector: (value: S, index: number) => R, defaultValue?: R): Observable<R>;
export function last<T, S extends T>(this: Observable<T>,
predicate: (value: T, index: number, source: Observable<T>) => value is S,
resultSelector: void,
defaultValue?: S): Observable<S>;
export function last<T>(this: Observable<T>,
predicate?: (value: T, index: number, source: Observable<T>) => boolean): Observable<T>;
export function last<T, R>(this: Observable<T>,
predicate: (value: T, index: number, source: Observable<T>) => boolean,
resultSelector?: (value: T, index: number) => R,
defaultValue?: R): Observable<R>;
export function last<T>(this: Observable<T>,
predicate: (value: T, index: number, source: Observable<T>) => boolean,
resultSelector: void,
defaultValue?: T): Observable<T>;
/* tslint:enable:max-line-length */
/**
* Returns an Observable that emits only the last item emitted by the source Observable.
* It optionally takes a predicate function as a parameter, in which case, rather than emitting
* the last item from the source Observable, the resulting Observable will emit the last item
* from the source Observable that satisfies the predicate.
*
* <img src="./img/last.png" width="100%">
*
* @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
* callback if the Observable completes before any `next` notification was sent.
* @param {function} predicate - The condition any source emitted item has to satisfy.
* @return {Observable} An Observable that emits only the last item satisfying the given condition
* from the source, or an NoSuchElementException if no such items are emitted.
* @throws - Throws if no items that match the predicate are emitted by the source Observable.
* @method last
* @owner Observable
*/
export function last<T, R>(this: Observable<T>, predicate?: (value: T, index: number, source: Observable<T>) => boolean,
resultSelector?: ((value: T, index: number) => R) | void,
defaultValue?: R): Observable<T | R> {
return higherOrder(predicate, resultSelector as any, defaultValue)(this);
}