/**
 * Generates random strings. By default this returns random 8 characters long
 * alphanumeric strings.
 * @param strLength The length of the output string. Defaults to 8.
 * @param charSet A string containing all the possible characters.
 *     Defaults to all the upper and lower-case letters plus digits.
 * @category Utility
 */
export declare function randomString(strLength?: number, charSet?: string): string;