dns wire format conversion

dnsWireFormat.js

function dnsWireFormat(domain, ttl, type, cls, address) {
    let labels = domain.split(".");
    let output = "";

    for (let label of labels) {
        output += label.length.toString(16).padStart(2, '0');
        for (let char of label) {
            output += char.charCodeAt(0).toString(16);
        }
    }

    output += "00";
    output += type.toString(16).padStart(4, '0');
    output += cls.toString(16).padStart(4, '0');
    output += ttl.toString(16).padStart(8, '0');

    let addrBytes = address.split(".");
    output += addrBytes.length.toString(16).padStart(4, '0');
    for (let byte of addrBytes) {
        output += parseInt(byte).toString(16).padStart(2, '0');
    }

    return output;
}

// types: A: (1) NS: (2), CNAME: (5), SOA: (6), PTR: (12), MX: (15), and AAAA: (28)
// classes IN: (1), CS: (2), CH (3), HS: (4)
console.log(dnsWireFormat("tanrikulu.eth", 3600, 1, 1, "1.2.3.4"));
// 0974616e72696b756c7503657468000001000100000e10000401020304