/**
 * 由小写字母组成的字符串
 *
 * @type {string}
 */
export declare const LOWER_CASE_LETTERS = "abcdefghijklmnopqrstuvwxyz";
/**
 * 由大写字母组成的字符串
 *
 * @type {string}
 */
export declare const UPPER_CASE_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
/**
 * 由数字组成的字符串
 *
 * @type {string}
 */
export declare const DIGITS = "0123456789";
/**
 * 要生成的随机字符串的类型的字符串名称常量对象
 */
export declare const RandomStrTypeConst: {
    readonly ALL: "ALL";
    readonly LOWER_CASE_LETTERS: "LOWER_CASE_LETTERS";
    readonly UPPER_CASE_LETTERS: "UPPER_CASE_LETTERS";
    readonly ALL_CASE_LETTERS: "ALL_CASE_LETTERS";
    readonly DIGITS: "DIGITS";
    readonly LOWER_CASE_LETTERS_DIGITS: "LOWER_CASE_LETTERS_DIGITS";
    readonly UPPER_CASE_LETTERS_DIGITS: "UPPER_CASE_LETTERS_DIGITS";
};
/**
 * 要生成的随机字符串类型
 */
export type RandomStrType = typeof RandomStrTypeConst[keyof typeof RandomStrTypeConst];
/**
 * 生成指定类型和长度的随机字符串<br/>
 *
 * @param {RandomStrTypeEnum} randomStrType 随机字符串类型
 * @param {number} len 随机字符串长度，如果小于等于 0，则直接返回空字符串
 * @returns {string} 指定类型和长度的随机字符串
 */
export declare const genRandomStr: (randomStrType: RandomStrType, len: number) => string;