Aldi socket node.js code

var PORT = 10000; // The port we're working withvar HOST = ''; // The address of our socket taken from discovery replyvar macAddress = ['0xac','0xcf','0x23','0x24','0x09','0x56']; // Our MAC address. Needed to do stuff with the socketvar macReversed = macAddress.slice().reverse(); // Copy MAC address to a new var so it doesn't get changed. then Reverse MAC address. Needed to 'subscribe' to the socketvar twenties = ['0x20', '0x20', '0x20', '0x20', '0x20', '0x20']; // This appears at the end of a few packets we send, so put it here for shortness of codevar payload = []; // The payload we're going to sendvar dgram = require('dgram'); // UDP supportvar server = dgram.createSocket('udp4'); // For receiving dataserver.bind(PORT); // Listen on port 10000 var client = dgram.createSocket('udp4'); // For sending datavar localIP = getBroadcastAddress();var broadcastip = localIP.substr(0,localIP.lastIndexOf('.')) + ".255";function discover() {    console.log('* DISCOVER')    payload = [];    payload = payload.concat(['0x68', '0x64', '0x00', '0x12', '0x71', '0x67'], macAddress, twenties); // Address discovery    sendMessage(payload, broadcastip); // Send it!} function subscribe() {    console.log('* SUBSCRIBE')    payload = [];    payload = payload.concat(['0x68', '0x64', '0x00', '0x1e', '0x63', '0x6c'], macAddress, twenties, macReversed, twenties); // Subscribe    sendMessage(payload, HOST);    setTimeout(on, 2000);    setTimeout(off, 4000);} function on() {    console.log('* TURN ON')    payload = [];    payload = payload.concat(['0x68', '0x64', '0x00', '0x17', '0x64', '0x63'], macAddress, twenties, ['0x00', '0x00', '0x00', '0x00', '0x01']); // ON    sendMessage(payload, HOST);}function off() {    console.log('* TURN OFF')    payload = [];    payload = payload.concat(['0x68', '0x64', '0x00', '0x17', '0x64', '0x63'], macAddress, twenties, ['0x00', '0x00', '0x00', '0x00', '0x00']); // OFF    sendMessage(payload, HOST);}discover(); //This is only needed if you do NOT know the IP address.function sendMessage(message, HOST) {    //console.log('Send Message of length: ' + message.length + ' to ' + HOST + ':' + PORT);    message = new Buffer(message);        client.send(message, 0, message.length, PORT, HOST, function(err, bytes) {        if (err) throw err;        console.log(' - Message sent');    });}       server.on('message', function (message, remote) {    if (remote.address != localIP) { //Check message isn't from me.        //console.log('Recieved Message of length: ' + message.length + ' from ' + remote.address + ':' + remote.port);                 var MessageHex = a2hex(message.toString())                  if (MessageHex.substr(0,12) == '686400177366') { //Check for power status command            switch(MessageHex.substr(MessageHex.length - 1,1)) {                case '0':                    console.log('* POWER STATUS: OFF');                    break;                case '1':                    console.log('* POWER STATUS: ON');                    break;                default:                    console.log('* POWER STATUS: UNKNOWN');                    break;            }                     }                if (HOST == '') { //First message received so save its IP address            console.log(' - Found HOST at ' + remote.address);            HOST = remote.address;            subscribe();        }    }});function getBroadcastAddress() {    var interfaces = require('os').networkInterfaces();    for (var devName in interfaces) {        var iface = interfaces[devName];        for (var i = 0; i < iface.length; i++) {            var alias = iface[i];            if (alias.family === 'IPv4' && alias.address !== '127.0.0.1' && !alias.internal) {                return alias.address;            }        }    }    return '0.0.0.0';}function a2hex(str) {    var arr = [];    for (var i = 0, l = str.length; i < l; i ++) {        var hex = Number(str.charCodeAt(i)).toString(16);        if (hex.length == 1) {            hex = "0" + hex;        }        arr.push(hex);    }    return arr.join('');}