/**
 * @param {Array} arr An array to process.
 */
export declare function to2dArray(arr: unknown[]): void;
/**
 * @param {Array} arr An array to extend.
 * @param {Array} extension The data to extend from.
 */
export declare function extendArray(arr: unknown[], extension: unknown[]): void;
/**
 * @param {Array} arr An array to pivot.
 * @returns {Array}
 */
export declare function pivot(arr: unknown[][]): unknown[];
/**
 * A specialized version of `.reduce` for arrays without support for callback
 * shorthands and `this` binding.
 *
 * {@link https://github.com/lodash/lodash/blob/master/lodash.js}.
 *
 * @param {Array} array The array to iterate over.
 * @param {Function} iteratee The function invoked per iteration.
 * @param {A} [accumulator] The initial value.
 * @param {boolean} [initFromArray] Specify using the first element of `array` as the initial value.
 * @returns {A} Returns the accumulated value.
 */
export declare function arrayReduce<T, A>(array: T[] | Iterable<T>, iteratee: (acc: A, value: T, index: number, array: T[]) => A, accumulator: A, initFromArray?: boolean): A;
/**
 * A specialized version of `.filter` for arrays without support for callback
 * shorthands and `this` binding.
 *
 * {@link https://github.com/lodash/lodash/blob/master/lodash.js}.
 *
 * @param {Array} array The array to iterate over.
 * @param {Function} predicate The function invoked per iteration.
 * @returns {Array} Returns the new filtered array.
 */
export declare function arrayFilter<T>(array: T[] | Iterable<T>, predicate: (value: T, index: number, array: T[]) => unknown): T[];
/**
 * A specialized version of `.map` for arrays without support for callback
 * shorthands and `this` binding.
 *
 * @param {Array} array The array to iterate over.
 * @param {Function} iteratee The function invoked per iteration.
 * @returns {Array} Returns the new filtered array.
 */
export declare function arrayMap<T, U>(array: T[] | Iterable<T>, iteratee: (value: T, index: number, array: T[]) => U): U[];
/**
 * A specialized version of `.forEach` for arrays without support for callback
 * shorthands and `this` binding.
 *
 * {@link https://github.com/lodash/lodash/blob/master/lodash.js}.
 *
 * @param {Array|*} array The array to iterate over or an any element with implemented iterator protocol.
 * @param {Function} iteratee The function invoked per iteration.
 * @returns {Array} Returns `array`.
 */
export declare function arrayEach<T>(array: T[] | Iterable<T>, iteratee: (value: T, index: number, array: T[]) => unknown): T[];
/**
 * Calculate sum value for each item of the array.
 *
 * @param {Array} array The array to process.
 * @returns {number} Returns calculated sum value.
 */
export declare function arraySum(array: number[]): number;
/**
 * Returns the highest value from an array. Can be array of numbers or array of strings.
 * NOTICE: Mixed values is not supported.
 *
 * @param {Array} array The array to process.
 * @returns {number} Returns the highest value from an array.
 */
export declare function arrayMax(array: number[]): number;
/**
 * Returns the lowest value from an array. Can be array of numbers or array of strings.
 * NOTICE: Mixed values is not supported.
 *
 * @param {Array} array The array to process.
 * @returns {number} Returns the lowest value from an array.
 */
export declare function arrayMin(array: number[]): number;
/**
 * Calculate average value for each item of the array.
 *
 * @param {Array} array The array to process.
 * @returns {number} Returns calculated average value.
 */
export declare function arrayAvg(array: number[]): number;
/**
 * Flatten multidimensional array.
 *
 * @param {Array} array Array of Arrays.
 * @returns {Array}
 */
export declare function arrayFlatten(array: unknown[]): unknown[];
/**
 * Unique values in the array.
 *
 * @param {Array} array The array to process.
 * @returns {Array}
 */
export declare function arrayUnique<T = unknown>(array: T[]): T[];
/**
 * Differences from two or more arrays.
 *
 * @param {...Array} arrays Array of strings or array of numbers.
 * @returns {Array} Returns the difference between arrays.
 */
export declare function getDifferenceOfArrays<T extends string | number>(...arrays: Array<T[]>): T[];
type IntersectionComparator = (a: string | number, b: string | number) => boolean;
type IntersectionArg = Array<string | number> | IntersectionComparator;
/**
 * Intersection of two or more arrays.
 *
 * @param {...Array<*|Function>} args Array of elements followed by a comparator function.
 * @returns {Array} Returns elements that exists in every array.
 */
export declare function getIntersectionOfArrays(...args: IntersectionArg[]): (string | number)[];
/**
 * Union of two or more arrays.
 *
 * @param {...Array} arrays Array of strings or array of numbers.
 * @returns {Array} Returns the elements that exist in any of the arrays, without duplicates.
 */
export declare function getUnionOfArrays(...arrays: Array<Array<string | number>>): (string | number)[];
/**
 * Convert a separated strings to an array of strings.
 *
 * @param {string} value A string of class name(s).
 * @param {string|RegExp} delimiter The pattern describing where each split should occur.
 * @returns {string[]} Returns array of string or empty array.
 */
export declare function stringToArray(value: string, delimiter?: string | RegExp): string[];
/**
 * Convert an array of strings to a single string.
 *
 * @param {string[]} array Array of strings.
 * @param {string} separator Separator string.
 * @returns {string} Returns a string made by joining all array elements with a separator.
 */
export declare function arrayToString(array: string[], separator?: string): string;
export {};