/**
 * @module CookieHelper
 * @category Cookie操作辅助类
 */
/**
 * 根据key值获取cookie数据
 * @example
 * ```ts
 * getItem('test');
 * ```
 * @param key key值
 * @returns Cookie中key值为key的值
 */
export declare function getItem(key: string): string;
/**
 * 根据key值获取cookie数据后删除Cookie中该键值对
 * @example
 * ```ts
 * getItemOnce('test');
 * ```
 * @param key key值
 * @returns Cookie中键值为key的值
 */
export declare function getItemOnce(key: string): string;
/**
 * 设置cookie的键值对
 * @example
 * ```ts
 * setItem('test', '你好, 世界!');
 * ```
 * @param key 键
 * @param val 值
 */
export declare function setItem(key: string, val: string): boolean;
/**
 * 根据key值删除Cookie中键值对
 * @example
 * ```ts
 * removeItem('test');
 * ```
 * @param key key值
 */
export declare function removeItem(key: string): void;
/**
 * 根据key值判断Cookie中是否存在键值对
 * @example
 * ```ts
 * exist('test');
 * ```
 * @param key - key值
 */
export declare function exist(key: string): boolean;
/**
 * 清空cookie
 * @example
 * ```ts
 * clear();
 * ```
 */
export declare function clear(): void;