javascript cpf validate

/**
 * exemplo de plugin jQuery
 *
 * @refer http://www.macoratti.net/alg_cpf.htm
 * @author J. Augusto <augustowebd.spam (a) gmail dot com
 * @date 2017-07-15
 */
(function ($){

    /**
     * @code
     * $('inputSelector').validaCpf()
     * @code
     *
     * @param String msgError
     */
    $.fn.validaCpf = function (msgError) {

        let lenAction = 11;

        $(this)
        .on('keyup', function () {
                let rawValue = this.value;
                let cleanValue = rawValue.replace(/[^\d]/gi, '');

                if (cleanValue.length == lenAction) {
                    if (! cpfAlgorithinValidate(cleanValue)) {
                        throw Error(
                            msgError
                            ? msgError
                            : 'Valor inválido'
                        );
                    }
                }

            })
            ;

        return this;
    };

})(jQuery);

let cpfAlgorithinValidate = function (val) {
    let digit_10 = val[val.length - 2];
    let digit_11 = val[val.length - 1];

    return (
        digit_10 === val.substr(0,  9).module11() &&
        digit_11 === val.substr(0, 10).module11()
    );
};

/**
 * Adiciona método de validacao de cpf à classe core.javascript.String
 *
 * @code
 *  "123456789".module11();
 *  "1234567890".module11();
 * @code
 *
 * @return string
 */
String.prototype.module11 = function () {
    let sum         = 0;
    let module11    = 11;
    let multiplier  = this.length + 1;

    for (let i = 0; i < this.length; i++) {
        sum += (multiplier - i) * parseInt(this[i]);
    }

    let resultMod = sum % module11;
    let result = resultMod < 2
               ? 0
               : module11 - resultMod
               ;

    return result + '';
}