Your First Bot

Now it's time to develop your first bot! If you haven't already, please make sure you've created a bot account and have installed discord.js - the Getting Started section should go through all of this.

We're also assuming that you've learned the basics of JavaScript, if you've not try taking a look at the CodeAcademy JavaScript course.

A really basic bot

Assuming you're good to go, let's start coding! In the getting started chapter, we went through creating a folder for your bot, creating a bot account (make sure you have its token) and installing a proper editor.

Open the editor you've chosen and create a new file, naming it something like bot.js. Make sure you save it in the folder you created for your bot.

One of the most basic bots you can create with discord.js is a simple ping-pong bot (you can copy this code into your editor and save it.)

const Discord = require('discord.js');
const client = new Discord.Client();

client.on('message', message => {
  if (message.content.startsWith('ping!')) {
    message.reply('pong!');
  }
});

client.on('ready', () => {
   console.log('I am ready!'); 
});

client.login('your bot token');

Replace your bot token with your bot's token, and open up a command prompt or terminal in your bot's folder. Run node bot.js and try sending ping! to a text channel the bot is in.

As a quick note, in this guide you may see "ES6" and wonder what we're referring to. JavaScript is also known as ECMAScript, and ES6 is a version of it.

Breaking it down

Before we start to look at developing a more useful bot, let's have a look at what is happening:

const Discord = require('discord.js');
const client = new Discord.Client();

This piece of code simply imports the discord.js library, and then creates a new Discord Client.

client.on('message', message => {
  if (message.content === 'ping!') {
    message.reply('pong!');
  }
});

This piece of code adds a "message" event listener. We'll talk more about message events later, but for now all you need to know is that whenever the client receives a message, it also fires out a message event. We can listen for this event if we want our bot to react to messages.

This particular event listener receives a message object, and then it checks to see if the message that was sent was ping!. If it was, then we reply to that message with pong!.

client.on('ready', () => {
   console.log('I am ready!'); 
});

This is another event listener for the ready event. Again, we'll talk about events later, but for now all you need to know is that when the ready event is fired, your bot is ready to start working.

What's next?

In the next chapter, we'll take a look at understanding the concept of events that we have touched on in this chapter.