Code

var Discord = require('discord.js')
var client = new Discord.Client()
var cmds = {}
var errorlvl

var prefix = '!'
function weAreReady() {
    console.log('The bot has successfully logged in.')
}

function addCmd(name, argNumber, cmd, usage) {
    cmds[name] = {name:name,func: cmd, usage: usage,argNum: argNumber}
}

client.on('ready', weAreReady)
client.on('message', function (message) {

    if (message.content.startsWith(prefix)) {
        cmd = message.content.split(prefix).pop()
        actualcmd = cmd.split('_').pop()
        var args
        if (cmds[actualcmd] == undefined) {
            //It is not a vailid command
            console.log('invalid cmd')
            console.log('cmd: ' + actualcmd)
        } else {
            //Get to actually parsing the command
            args = cmd.split(cmd).pop().split('_')
            console.log(args)
            console.log(cmds[actualcmd].argNum)
            if (args.length === cmds[actualcmd].argNum + 1) {

                //Correct number of args
                args.unshift(message);
                cmds[actualcmd].func.apply(this, args)
            } else {

                cmds[actualcmd].usage(message)
            }


        }
    }
})

addCmd('hello', 0, function (message) {
    message.channel.send('Hello, ' + message.author.username)
    errorlvl = 0
}, function (message) {
    errorlvl = 1
    message.channel.send(message.author.username + ', the arguments are not complete. The full usage of this command is: !hello')
})
client.login('MzE4ODk2MDM5NDM4NDUwNjk5.DA5Cuw.EyshBBnXnrETKf2KPU-MKclulpg')