index.js

require("dotenv").config();
const fs = require("fs");
const Discord = require("discord.js");
const bot = new Discord.Client();
const mongoose = require("mongoose");
const TOKEN = process.env.TOKEN;
const PREFIX = "!";

bot.commands = new Discord.Collection();
const commandFiles = fs
  .readdirSync("./commands")
  .filter((file) => file.endsWith(".js"));

const cooldowns = new Discord.Collection();
for (const file of commandFiles) {
  const command = require(`./commands/${file}`);

  // set a new item in the collection
  // with the key as the command name and the value as the exported module
  bot.commands.set(command.name, command);
}

bot.once("ready", () => {
  console.log("Ready!");
});

bot.on("message", (message) => {
  if (!message.content.startsWith(PREFIX) || message.author.bot) {
    return;
  }

  const args = message.content.slice(PREFIX.length).split(/ +/);
  const commandName = args.shift().toLowerCase();

  const command =
    bot.commands.get(commandName) ||
    bot.commands.find(
      (cmd) => cmd.aliases && cmd.aliases.includes(commandName)
    );

  if (!command) {
    message.channel.send(
      "Invalid command! Type !help to get list of all commands."
    );
    return;
  }
  // for commands that require an argument but not provided
  if (command.args && !args.length) {
    let reply = `You didn't provide any arguments, ${message.author}!`;
    if (command.usage) {
      reply += "\nThe proper usage would be: ";
      reply += `\`${PREFIX}${command.name} ${command.usage}\``;
    }
    return message.channel.send(reply);
  }
  if (command.guildOnly && message.channel.type !== "text") {
    return message.reply("I can't execute this command inside DMs!");
  }
  if (!cooldowns.has(commandName)) {
    cooldowns.set(commandName, new Discord.Collection());
  }
  const now = Date.now();
  const timestamps = cooldowns.get(commandName);
  const cooldownAmount = (command.cooldown || 3) * 1000;
  if (timestamps.has(message.author.id)) {
    const expirationTime = timestamps.get(message.author.id) + cooldownAmount;
    if (now < expirationTime) {
      const timeLeft = (expirationTime - now) / 1000;
      return message.reply(
        `Please wait ${timeLeft.toFixed(
          1
        )} more second(s) before reusing the \`${command.name}\` command.`
      );
    }
  } else {
    timestamps.set(message.author.id, now);
    setTimeout(() => timestamps.delete(message.author.id), cooldownAmount);
  }

  try {
    command.execute(message, args);
  } catch (error) {
    console.log(error);
    message.reply("There was an error trying to execute that command!");
  }
});

bot.login(TOKEN);

// connect with mongoose
mongoose.connect(
  `mongodb+srv://${process.env.NAME}:${process.env.PASSWORD}@rajucp-xph1k.mongodb.net/CodingBot?retryWrites=true&w=majority`,
  {
    useNewUrlParser: true,
    useUnifiedTopology: true,
    useFindAndModify: false,
    useCreateIndex: true,
  },
  (err) => {
    if (err) {
      console.log(err);
      return;
    }
    console.log("Connected");
  }
);