calculaDv

calculaDv.js

function calculaDVGtin(digits) {
    if (isNaN(digits)) return null;

    var code = (digits).toString(),
        even = odd = 0;

    for (var i = code.length - 1; i >= 0; --i) {
        if ((code.length - i) % 2 == 0) {
            odd += Number(code.charAt(i));
        } else {
            even += Number(code.charAt(i));
        }
    }
    var check = 10 - ((even * 3 + odd) % 10);

    return (check >= 10) ? 0 : check;
}

function calculaDVModulo10(digits) {
    if (isNaN(digits)) return null;

    var code = (digits).toString(),
         sum = 0;

    for (i = 0; i < code.length; ++i) {
        number = Number(code.charAt(i)) * ((i % 2 == 0) ? 2 : 1);
        if (number == 10) {
            ++sum;
        } else if (number < 10) {
            sum += number;
        } else {
            sum += number / 10 + number % 10;
        }
    }
    return (10 - (sum % 10));
}

function calculaDVModulo11(digits) {
    if (isNaN(digits)) return null;

    var code = (digits).toString(),
         sum = 0,
      factor = 2;

    for (i = code.length - 1; i >= 0; --i) {
        sum += Number(code.charAt(i)) * factor;
        if (++factor <= 9) continue;
        factor = 2;
    }
    var check = 11 - (sum % 11);

    return (check >= 10) ? 0 : check;
}