Discord Bot: APP.JS (custom prefix)

const Discord  = require("discord.js");
const Config = require("./config.json");
const Token = require("./token.json");
const fs = require("fs");
const Core = require("./core.js");

const bot = new Discord.Client({disableEveryone: true});
bot.commands = new Discord.Collection();

fs.readdir("./commands/", (err, files) =>{
    if(err) console.log(err);
    let jsfile = files.filter(f => f.split(".").pop() === "js");
    if(jsfile.lenght <= 0){
        console.log("Commands failed to load.");
        return;
    }

    jsfile.forEach((f, i) =>{
    let props = require(`./commands/${f}`);
    console.log(`${f} loaded!`);
    bot.commands.set(props.help.name, props);
    });
});

bot.on("ready", async () =>{
console.log(`${bot.user.username} is online! Running on ${bot.guilds.size} servers!`);
console.log(Core.randNum(1, 100));
bot.user.setActivity("Work In Progress", {type: "STREAMING"});
    });

    bot.on("guildMemberAdd", async member =>{
        let welcomeChannel = member.guild.channels.find(`name`, "joining-people");
        if(!welcomeChannel) return;
        welcomeChannel.send(`Welcome ${member} to Gaming n' Talking!`);
        //Sample Text
        Core.send(welcomeChannel, member, "Welcome to Gaming n' Talking! Please remember to read the rules, before continuing.", "DMs are disabled for you, please remember to read rules");;
    });

    bot.on("guildMemberRemove", async member =>{
        let welcomeChannel = member.guild.channels.find(`name`, "joining-people");
        if(!welcomeChannel) return;
        welcomeChannel.send(`Goodbye,  ${member} , It was nice meeting you! `);
        //Sample Text
    member.send("We're very sad you left, aaaaa").catch(O_o=>{ welcomeChannel.send("Leaving user doesn't have DMs enabled!")});
    });


    bot.on("message", async message =>{
if(message.author.bot) return;
if(message.channel.type === "dm") return;

let settings = JSON.parse(fs.readFileSync(./settings.json", "utf8"));
if(!settings[message.guild.id]){
    settings[message.guild.id] = {
        prefix: Config.prefix
    };
}

let prefix = settings[message.guild.id].prefix;
let msgArray = message.content.split(" ");
let cmd = msgArray[0];
if(cmd.slice(0, prefix.length) !== prefix) return;
let args = msgArray.slice(1);
let cmdFile = bot.commands.get(cmd.slice(prefix.length))
if(cmdFile) cmdFile.run(bot, message, args);
    });

    bot.login(Token.token);