import React from 'react';
/**
 * Merges multiple React refs into a single callback ref.
 *
 * @param {Array<React.MutableRefObject<T> | React.LegacyRef<T>>} refs - The array of refs to be merged.
 * @return {React.RefCallback<T>} A callback ref that sets each provided ref to the same value.
 */
export declare function mergeRefs<T = any>(refs: Array<React.MutableRefObject<T> | React.LegacyRef<T>>): React.RefCallback<T>;
/**
 * Clamps a number between an upper and lower bound.
 *
 * @param {number} number - The input number.
 * @param {number} min - The lower boundary.
 * @param {number} max - The upper boundary.
 * @return {number} The clamped number.
 */
export declare function clamp(number: number, min: number, max: number): number;
/**
 * Capitalizes the first letter of the given word and makes the rest of the word lowercase.
 *
 * @param {string} word - The word to capitalize. Defaults to an empty string if no word is provided.
 * @return {string} The input word with the first letter capitalized and the rest of the word in lowercase.
 *
 * @example
 * // returns "Hello"
 * capitalize("hello");
 *
 * @example
 * // returns "World"
 * capitalize("WORLD");
 */
export declare function capitalize(word?: string): string;
/**
 * Creates an array of numbers (positive integers) ranging from 0 to the specified value.
 *
 * @param {number} len - The length of the desired array. This also determines the range of numbers in the array.
 * @return {number[]} An array of numbers ranging from 0 to len - 1.
 *
 * @example
 * // returns [0, 1, 2, 3, 4]
 * range(5);
 */
export declare const range: (len: number) => number[];
/**
 * Groups the elements of an array based on the given criteria.
 *
 * @param {any[]} arr - The array to group.
 * @param {string} criteria - The property name to group the array by.
 * @return {object} An object with keys representing the grouped criteria and values as arrays of items belonging to that group.
 *
 * @example
 * groupBy([{ 'group': 'group1', 'value': 1 }, { 'group': 'group2', 'value': 2 }], 'group');
 * // returns { 'group1': [{ 'group': 'group1', 'value': 1 }], 'group2': [{ 'group': 'group2', 'value': 2 }] }
 */
export declare const groupBy: (arr: any[], criteria: string) => object;