A basic irc client/bot in node.js

irc.js

var pr = console.log;

var net = require('net');
var readline = require('readline');

//Simple IRC client

function IRC(ip, port, nick, room, debug) {
    this.ip = ip;
    this.port = port;
    this.room = room;
    this.nick = nick;
    this.debug = debug;
    this.maxMsgLen = 250;
    this.loginCmdWait = 5000;
    this.pingInterval = 100000;
    
    this.prefix = ':'+this.nick+'!~'+'irc.js ';
    this.handlers = {};
    
    this.socket = net.Socket({readable: true, writable:true});
    
    var that = this;
    this.rl = readline.createInterface({
        input: that.socket
    });
    
    this.socket.setEncoding('utf8');
    
    function delayMsg(f) {
      setTimeout(f, that.loginCmdWait);
    }
    
    this.socket.on('connect', function () {
        that.debug && pr('Connected.');
        that.sendMsg('NICK', that.nick, delayMsg(function () {
            that.sendMsg('USER', that.nick+' 0 * :Real name', delayMsg(function () {
                that.sendMsg('JOIN', ':'+that.room, delayMsg(function () {
                    that.handlers.connect && that.handlers.connect();
                    if (that.pingInterval) {
                      setInterval(() => {
                        that.sendMsg('PING', Math.floor(Math.random()*1e6));
                      }, that.pingInterval);
                    }
                }));
            }));
        }));
    });
    
    var pingRE = /^PING \:([^\s]+)/;
    var messageRE = new RegExp(':([^\\s]+)\\sPRIVMSG\\s'+this.room+'\\s:(.+)', 'i');
    var nickRE = /^([^\s\!]+)/;
    
    this.rl.on('line', function (line) {
        that.debug && pr('Received:',line);
        var _match;
        if (_match = line.match(pingRE)) {
            that.debug && pr('PING',_match[1]);
            that.sendMsg('PONG',':'+_match[1]);
        } else if (_match = line.match(messageRE)) {
            //that.debug && pr('Matches:',_match);
            var nick = _match[1].match(nickRE)[1];
            var msg = _match[2];
            that.handlers.message && that.handlers.message(nick, msg);
        }
    });
    
    this.socket.connect({host: ip, port:port});
}

IRC.prototype.on = function(event, handler) {
    this.handlers[event] = handler;
};

IRC.prototype.sendMsg = function(cmdName, data, onDone) {
    var that = this;
    this.socket.write(this.prefix+cmdName+' '+data+'\n', 'utf8', function () {
        that.debug && pr('Sent:',cmdName,data);
        onDone && onDone.apply(that, arguments);
    });
};

//Splits messages that are longer than this.maxMsgLen (== 445 by default) bytes when utf encoded
//into multiple msgs
IRC.prototype.send = function(str, onDone) {
    
    var blen = Buffer.byteLength(str, 'utf8');
    var msgs = [];
    
    //Split long messages into chunks, reverse the chunk array so you can send chunks by .pop()
    //until array is empty
    if (blen > this.maxMsgLen) {
        this.debug && pr('msg length:',blen);
        var rightPart = str;
        do {
            msgs.push(rightPart.substr(0, this.maxMsgLen));
            rightPart = rightPart.substr(this.maxMsgLen);
        } while (rightPart.length > this.maxMsgLen)
        rightPart.length && msgs.push(rightPart);
        msgs.reverse();
        this.debug && pr(msgs);
    } else {
        //Short messages are just arrays of one chunk
        msgs = [str];
    }
    
    var that = this;
    
    function send() {
        if (msgs.length) {
            var data = msgs.pop();
            that.sendMsg('PRIVMSG', that.room+' :'+data, send);
        } else {
            onDone && onDone.apply(that, arguments);
        }
    }
    
    send();
};

// How to use

var ip = '80.65.57.18'; //one of irc.rizon.net IPs
var port = 6667; //UTF8
var room = '#r9kprog';
var nick = 'testbot891023';

var client = new IRC(ip, port, nick, room, true);

client.on('message', function(nick, msg) {
    pr('Message from',nick+':',msg);
    if (msg.match(/^[Nn]ode/)) {
        client.send(nick+' told me that "'+msg+'", I remember everything!');
    }
});

client.on('connect', function () {
    client.send('Node connected.');
});

//module.exports = IRC;