discord.js/examples/tonicdev.js

var Discord = require('discord.js');

const token = ''; // token for bot login

//when the bot is ready
bot.on("ready", () => {
	console.log(`Ready to begin! Serving in ${bot.channels.length} channels`);
});

//when the bot disconnects
bot.on("disconnected", () => {
	//alert the console
	console.log("Disconnected!");

	//exit node.js with an error
	process.exit(1);
});

//when the bot receives a message
bot.on("message", msg => {
	//if message begins with "ping"
	if (msg.content.startsWith("ping")) {
		//send a message to the channel the ping message was sent in.
		bot.sendMessage(msg, "pong!");

		//alert the console
		console.log("pong-ed " + msg.author.username);
	}
});

bot.loginWithToken(token);