index.js

const Discord = require("discord.js");
const client = new Discord.Client();
const config = require("./config.json"),
const alive = require("./alive.js")
fs = require("fs"),
util = require("util"),
readdir = util.promisify(fs.readdir),
mongoose = require("mongoose");

client.on('guildCreate', guild => {
 guild.systemChannel.send(`Hey ! Don't Forget Vote Me !`)
})
client.on('guildLeave', guild => {
 guild.systemChannel.send(`Thanks ! Using My Bot, By Owner`)
})
client.on('message', message => {
    if (message.content === '!join') {
        client.emit('guildMemberAdd', message.member);
    }
});

client.on('message', message => {
    if (message.content === '!leave') {
        client.emit('guildMemberLeave', message.member);
    }
});

client.on('message', message => {
    if (message.content === '!nitro') {
        client.emit('GuildMember.premiumSinceTimestamp', message.member);
    }
});

client.logger = require("./modules/Logger.js");
client.errors = require("./modules/Embeds.js");
client.tools = require("./modules/Tools.js");
client.data = require("./modules/MongoDB.js");

client.events = new Discord.Collection();
client.commands = new Discord.Collection();
client.categories = [];
async function init(){

const eventFiles = fs.readdirSync('./events/').filter(file => file.endsWith('.js'));
for (const file of eventFiles) {
    const event = require(`./events/${file}`);
    const eventName = file.split(".")[0];
    client.logger.event(`Loading Event - ${eventName}`);
    client.on(eventName, event.bind(null, client));
}

let folders = await readdir("./commands/");
folders.forEach(direct =>{
  const commandFiles = fs.readdirSync('./commands/' + direct + "/").filter(file => file.endsWith('.js'));
  for (const file of commandFiles) {
      const command = require(`./commands/${direct}/${file}`);
      client.commands.set(command.name, command);
  }
  })
  
  mongoose.connect(process.env.mongoDB, { useNewUrlParser: true, useUnifiedTopology: true }).then(() => {
      client.logger.log("Connected to the Mongodb database.", "log");
  }).catch((err) => {
      client.logger.log("Unable to connect to the Mongodb database. Error:"+err, "error");
  });


}

init();
client.login(process.env.TOKEN);