import { Observable } from '../Observable';
/**
 * 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%">
 *
 * @param {function} predicate - the condition any source emitted item has to satisfy.
 * @returns {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.
 */
export declare function last<T, R>(predicate?: (value: T, index: number, source: Observable<T>) => boolean, resultSelector?: (value: T, index: number) => R, defaultValue?: R): Observable<T> | Observable<R>;