/**
 * If the browser supports localStorage, set the value of the key to the value.
 *
 * @param {string} key - The key to store the value under.
 * @param {string} value - The value to be stored.
 */
export declare function setItem(key: string, value: unknown): void;
/**
 * If the browser supports localStorage, return the value of the key, otherwise return null.
 *
 * @typedef T generic type
 * @param {string} key - The key of the item you want to get.
 * @returns {T | null} A any type
 */
export declare function getItem<T>(key: string): T | null;