Added BotClient.

package.json

@@ -2,7 +2,7 @@
   "name": "d.js-v12-bot",
   "version": "0.0.1",
   "description": "A Discord bot built on Discord.JS v12",
-  "main": "index.js",
+  "main": "src/index",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },

src/Structures/BotClient.js

@@ -0,0 +1,50 @@
+const { Client } = require('discord.js');
+
+module.exports = class BotClient extends Client {
+
+	constructor(options = {}) {
+		super({
+			disableMentions: 'everyone'
+		});
+		this.validate(options);
+
+		this.once('ready', () => {
+			console.log(`Logged in as ${this.user.username}.`);
+		});
+
+		this.on('message', async (message) => {
+			const mentionRegex = RegExp(`^<@!${this.user.id}>$`);
+			const mentionRegexPrefix = RegExp(`^<@!${this.user.id}> `);
+
+			if (!message.guild || message.author.bot) return;
+
+			if (message.content.match(mentionRegex)) message.channel.send(`My prefix for ${message.guild.name} is \`${this.prefix}\`.`);
+
+			const prefix = message.content.match(mentionRegexPrefix) ?
+				message.content.match(mentionRegexPrefix)[0] : this.prefix;
+
+			// eslint-disable-next-line no-unused-vars
+			const [cmd, ...args] = message.content.slice(prefix.length).trim().split(/ +/g);
+
+			if (cmd.toLowerCase() === 'hello') {
+				message.channel.send('Hello!');
+			}
+		});
+	}
+
+	validate(options) {
+		if (typeof options !== 'object') throw new TypeError('Options should be a type of Object.');
+
+		if (!options.token) throw new Error('You must pass a token for the client.');
+		this.token = options.token;
+
+		if (!options.prefix) throw new Error('You must pass a prefix for the client.');
+		if (typeof options.prefix !== 'string') throw new TypeError('Prefix should be a type of String.');
+		this.prefix = options.prefix;
+	}
+
+	async login(token = this.token) {
+		super.login(token);
+	}
+
+};

src/index.js

@@ -1,5 +1,5 @@
-const BotClient = require("./Structures/BotClient");
-const config = require("../config.json");
+const BotClient = require('./Structures/BotClient');
+const config = require('../config.json');
 
 const client = new BotClient(config);
-client.login();
+client.login();