/**
 * @packageDocumentation
 * @module Array
 */
import { OperatorFunction } from 'rxjs';
import { PredicateFn } from '../types/generic-methods';
/**
 * Returns an Observable array of truthy values from a source Array or Set
 * When working with data, if the array contains numbers `0` will be returned as a value to the [[PredicateFn]], but all
 * other falsy values will be ignored
 *
 * @category Filter
 *
 * @param predicate Optional [[PredicateFn]] used to get a truthy value of array values
 *
 * @example
 * Return an array of all numbers that are truthy
 * ```ts
 * const input = [0, 10, 1, 0, 6, 6, 0, 1];
 * of(input).pipe(findAll()).subscribe();
 * ```
 * Output: `[10, 1, 6, 6, 1]`
 *
 * @example
 * Return an array of values where the source array value length `>= 5`
 * ```ts
 * const input = ['', '', 'Hello', 'RxJS', 'Ninja'];
 * of(input).pipe(findAll(v => v.length >= 5)).subscribe();
 * ```
 * Output: `['Hello', 'Ninja']`
 *
 * @returns An Observable that emits an array containing all truthy values from a source array
 */
export declare function findAll<T extends unknown>(predicate?: PredicateFn<T>): OperatorFunction<Iterable<T>, T[]>;