checkdigit calculation for HP-17b

[Thomas Klemm]

(07-29-2015 01:52 AM)Thomas Klemm Wrote:  This looks like duplicated code that could be extracted to a separate function.

Maybe something like this?

Code:

function checkCPF(cpf) {
    if (cpf == "00000000000") {
        return false;
    }
    return verify(cpf) && verify(cpf.substring(1));
}

function verify(value) {
    var CHECK = 9;
    var digit = value.split("");
    var sum = 0;
    for (var i = 0; i < CHECK; i++) {
        sum += digit[i] * (i + 1);
    }
    return (sum % 11) % 10 == digit[CHECK];
}

At least that makes it more apparent that you run the same verification twice.
The 2nd time just shifted by one digit.

Cheers
Thomas