/**
 * Copyright (c) 2017-present A. Matías Quezada <amatiasq@gmail.com>
 */
/**
 * Retuns every possible combination of a given set of elements.
 *
 * @example
 * combinations('abc'.split(''), 2);
 * > [['a'], ['b'], ['c'], ['a', 'b'], ['a', 'c'], ['b', 'a'], ['b', 'b'] ...]
 *
 * @param {Array} array Elements to combine.
 * @param {Number} length Max length for resulted combinations.
 * @returns {Array} A list with all the possible combinations.
 */
export default function combinations<T>(array: T[], length: number): T[][];