node-irc with Twitch.TV重复消息问题

Question

我的node-irc bot有时会重复聊天中的内容。有时它完美无缺;其他时候它重复。我查看了整个代码，无法发现任何递归。

连接功能（与我的听众一起）

//connects the bot to the channel
this.connectToChannel = function(callback) {
    console.log("Connection");
    botInstance.connect();
    botInstance.join(currentChannel, function(){
        botInstance.say(currentChannel, initalConnectionMessage);
        console.log("Joined");
        callback();
    });
    botInstance.addListener("message", function(nick, to, text, message) {
        if (text == lastText){
            return; // you can i've tried to avoid this issue
        }

        bannedWords.forEach(function(item,index){
            if (text.includes(item)){
                parent.sendMessage(nick + " > You're not allowed to use that type of language.");
                parent.sendMessage("/timeout " + nick + " 10");
            }
        });

        commands.forEach(function(item, index){
            var splitData = text.split(' ');

            if (splitData[0] == item.getExecutor()) {
                //running this command

                var response = item.getResponse();
                response = response.replace("%user%", nick);
                response = response.replace("%bot_username%", config.botName);

                parent.sendMessage(response);
            }
        });
    });
}

Bot Creation（在连接之前调用此方法）

this.createBot = function(channel) {
    currentChannel = channel;

    var irc = require('irc');
    botInstance = new irc.Client(config.server, config.botName, {
        channels: [currentChannel + " " + config.oAuth],
        userName: config.botName,
        password: config.oAuth
    });
}

Bot发送消息

this.sendMessage = function(msg){
if(botInstance != null) {
    botInstance.say(currentChannel, msg);
    lastMessage = msg;
}