index.js

/* Defining Variables and Loggin into the Client/Bot */
const Discord = require("discord.js");
const fs = require("fs");
const client = new Discord.Client( {
  partials: ['USER', 'CHANNEL', 'GUILD_MEMBER', 'REACTION', 'MESSAGE'] // partials so I can include role reactions in this same bot.
});
const config = require("./config.json");
// We also need to make sure we're attaching the config to the CLIENT so it's accessible everywhere!
client.config = config;

/* Adding Events & Commands to bot */

/* Adding Events to bot */
fs.readdir("./events/", (err, files) => {
  if (err) return console.error(err);
  files.forEach(file => {
    const event = require(`./events/${file}`);
    let eventName = file.split(".")[0];
    client.on(eventName, event.bind(null, client));
  });
});

/* Reading Commands Files for usage */
client.commands = new Discord.Collection();
const commandFiles = fs.readdirSync('./commands').filter(file => file.endsWith('.js'));
for (const file of commandFiles) {
    console.log(file.slice(0,-3));
    const command = require(`./commands/${file.slice(0,-3)}`)
    client.commands.set(command.name, command);
}

/* Database Stuffs */
let connection;
const guildCommandPrefixes = new Map(); // Creates a new map for per-server prefixes

/* Displays that the bot was logged in and loads the per-server prefixes */
client.on('ready', () => {
  const Guilds = client.guilds.cache.map(guild => guild.id);
    console.log('Guilds: ' + Guilds);
  console.log(client.user.tag + " has logged in.");
  client.guilds.cache.forEach (guild => {
    connection.query (
      `SELECT cmdPrefix FROM GuildConfigurable WHERE guildId = '${guild.id}'`
    ).then(result => {
      guildCommandPrefixes.set(guild.id, result[0][0].cmdPrefix);
    }).catch(err => console.log(err))
  });

     // Sends embed when bot is reloaded
     const onEmbed = new Discord.MessageEmbed() // WORKS!
     .setColor('#000000')
     .setFooter(`The bot is now online. :) If you have issues please ping cute.as.ducks#8061 (Erin).`);
     let channel = client.channels.cache.find(c => c.id === '776192612671553578');

     channel.send(onEmbed);

    // Sets Bot's Status
    client.user.setPresence({
      status: "dnd",
      activity: {
          name: "++help",
          type: "PLAYING"
      }
    });
});

/* Adds Guilds to SQL table if there isn't already a row for the guild */
client.on('guildCreate', async (guild) => {
  try {
    await connection.query(
      `INSERT INTO Guilds VALUES('${guild.id}', '${guild.ownerID}')`
    );
    await connection.query(
      `INSERT INTO GuildConfigurable (guildId) VALUES ('${guild.id}')`
    );
  } catch(err) {
    console.log(err);
  }
});

/* commands for per-server prefix */
client.on('message', async (message) => {
  if(message.author.bot) return;
  const prefix = guildCommandPrefixes.get(message.guild.id);
  if(message.content.toLowerCase().startsWith(prefix + 'ping')) {
    message.channel.send(`Pong! You triggered this command with the prefix: ${prefix}`);
  } else if(message.content.toLowerCase().startsWith(prefix + 'changeprefix')) {
    if(message.member.id === message.guild.ownerID) {
      const [ cmdName, newPrefix ] = message.content.split(" ");
      if(newPrefix) {
        try {
          await connection.query(
            `UPDATE GuildConfigurable SET cmdPrefix = '${newPrefix}' WHERE guildId = '${message.guild.id}'`
          );
          guildCommandPrefixes.set(message.guild.id, newPrefix);
          message.channel.send(`Updated guild prefix to ${newPrefix}`);
        } catch(err) {
          console.log(err);
          message.channel.send(`Failed to update guild prefix.`);
        }
      } else {
        message.channel.send('❗ Please tell me what prefix you would like, I can\'t update the prefix unless you tell me. You should format this command like so: ' + `\`[originalprefix]changeprefix [newprefix]\``);
      }
    } else {
      message.channel.send('❌ You do not have permission to use this command. Only guild owners can change this command.')
    }
  }
});

/* Async function to login to database and the bot itself */
(async () => {
  connection = await require('../database/db.js');
  await client.login(config.token);
})();