discord.js Tutorial - Part 1

config.json

{
  "token": "YOUR TOKEN HERE",
  "owner": "YOUR DISCORD ID HERE",
  "prefix": "::"
}

main.js

const Discord = require('discord.js')
const fs      = require('fs')

// Read out content of 'config.json' synchronous and
// parse it to a javascript object
const config = JSON.parse(fs.readFileSync('config.json', 'utf8'))

// Creating instance of discord  bot client
var client = new Discord.Client()

// Ready Event:
// Fires when bot is logged in and ready to react on other events
client.on('ready', () => {
    console.log(`Logged in as ${client.user.username}...`)
})

// Refer command invokes to functions
var chdmap = {
    say: cmd_say,
    test: cmd_test
}

/**
 * Command function for say command
 * @param {Discord.Message} msg 
 * @param {string[]} args 
 */
function cmd_say(msg, args) {
    msg.channel.send(args.join(' '))
}

/**
 * Command function for test command
 * @param {Discord.Message} msg 
 * @param {string[]} args 
 */
function cmd_test(msg, args) {
    console.log("test")
}

// Message Event:
// Fires when any message was send into a channel,
// the bot is able to read in
client.on('message', (msg) => {

    // Getting content, sender, channel and guild out of message object
    var cont   = msg.content,
        author = msg.member,
        chan   = msg.channel,
        guild  = msg.guild

    // Only interpret when message was not send by bot self and if the
    // message content starts with the prefix string
    if (author.id != client.user.id && cont.startsWith(config.prefix)) {

        // ::say hello world!
        var invoke = cont.split(' ')[0].substr(config.prefix.length),
            args   = cont.split(' ').slice(1)

        if (invoke in cmdmap) {
            cmdmap[invoke](msg, args)
        }
    }

})

// Login client
client.login(config.token)

package.json

{
  "name": "tutorialjsbot",
  "version": "1.0.0",
  "description": "",
  "main": "src/main.js",
  "scripts": {
    "test": "node main.js",
    "start": "node main.js debug"
  },
  "author": "",
  "licence": "ISC",
  "dependencies": {
    "discord.js": "^11.2.1",
    "colors": "^1.1.2"
  }
}