IBAN validator

iban-validator.js

function ibanValidate(input) {
    function mod97(string) {
        var checksum = string.slice(0, 2), fragment;
        for (var offset = 2; offset < string.length; offset += 7) {
            fragment = String(checksum) + string.substring(offset, offset + 7);
            checksum = parseInt(fragment, 10) % 97;
        }
        return checksum;
    }

    var CODE_LENGTHS = {
        AD: 24, AE: 23, AT: 20, AZ: 28, BA: 20, BE: 16, BG: 22, BH: 22, BR: 29,
        CH: 21, CR: 21, CY: 28, CZ: 24, DE: 22, DK: 18, DO: 28, EE: 20, ES: 24,
        FI: 18, FO: 18, FR: 27, GB: 22, GI: 23, GL: 18, GR: 27, GT: 28, HR: 21,
        HU: 28, IE: 22, IL: 23, IS: 26, IT: 27, JO: 30, KW: 30, KZ: 20, LB: 28,
        LI: 21, LT: 20, LU: 20, LV: 21, MC: 27, MD: 24, ME: 22, MK: 19, MR: 27,
        MT: 31, MU: 30, NL: 18, NO: 15, PK: 24, PL: 28, PS: 29, PT: 25, QA: 29,
        RO: 24, RS: 22, SA: 24, SE: 24, SI: 19, SK: 24, SM: 27, TN: 24, TR: 26
    };
    var iban = String(input).toUpperCase().replace(/[^A-Z0-9]/g, ''), // keep only alphanumeric characters
        code = iban.match(/^([A-Z]{2})(\d{2})([A-Z\d]+)$/), // match and capture (1) the country code, (2) the check digits, and (3) the rest
        digits;
    // check syntax and length
    if (!code || iban.length !== CODE_LENGTHS[code[1]]) {
        return false;
    }
    // rearrange country code and check digits, and convert chars to ints
    digits = (code[3] + code[1] + code[2]).replace(/[A-Z]/g, function (letter) {
        return letter.charCodeAt(0) - 55;
    });

    // final check
    return mod97(digits);
}

var ibanCorrectArray = [
    "GB29 NWBK 6016 1331 9268 19",
    "DE89 3704 0044 0532 0130 00",
    "KZ75 125K ZT10 0130 0335",
    "NL91 ABNA 0417 1643 00"
];

var ibanNotCorrectArray = [
    "0483 5062 6661 8100 0",
    "GB29 0483 5062 6661 8100 0",
    "NL91 0483 5062 6661 8100 0",
    "KZ75 0483 5062 6661 8100 0"
];

ibanCorrectArray.map(function (item) {
    console.log(
        "Iban correct array: " + ibanValidate(item)
    );
});

ibanNotCorrectArray.map(function (item) {
    console.log(
        "Iban not correct array: " + ibanValidate(item)
    );
});