/** **************************
 * China mobile phone number *
 *****************************/
/**
 * starts with 1, second digit is 3, 4, 5, 6, 7, 8, or 9
 * reference: https://en.wikipedia.org/wiki/Telephone_numbers_in_China
 */
export declare function is_cn_mobile_phone_prefix(tel: string): boolean;
/**
 * with/without +86 prefix
 */
export declare function is_cn_mobile_phone(tel: number | string): boolean;
/**
 * @returns +86xxxxxxxxxx if valid
 *          empty string if not valid
 *
 * should be 1xx-XXXX-XXXX (except for 140–144, which are 13-digit IoT numbers)
 * in which the first three digits (13x to 19x) designate the mobile phone service provider.
 */
export declare function to_full_cn_mobile_phone(tel: string | number): string;
/**
 * @returns +86 1nn xxxx xxxx if valid
 */
export declare function format_cn_mobile_phone(tel: string | number): string;