Giveaway bot sample for twitch

bot.js

const tmi = require('tmi.js');

// Define configuration options
const opts = {
  identity: {
    username: <BOT_USERNAME>,
    password: <OAUTH_TOKEN>
  },
  channels: [
    <CHANNEL_NAME>
  ]
};
// Create a client with our options
const client = new tmi.client(opts);

// Register our event handlers (defined below)
client.on('message', onMessageHandler);
client.on('connected', onConnectedHandler);

// Connect to Twitch:
client.connect();

var participants = [];

// Called every time a message comes in
function onMessageHandler (target, context, msg, self) {
  if (self) { return; } // Ignore messages from the bot

  // Remove whitespace from chat message
  const commandName = msg.trim();

  // If the command is known, let's execute it
  if (commandName === '!giveaway') {
    const participant = context.username;
    if (participants.indexOf(participant) == -1) {
        participants.push(participant);
        client.say(target, `${participant} joined the giveaway`);
    } else {
        client.say(target, `${participant} have already registered before`);
    }
    console.log(`* Executed ${commandName} command`);
  } else if (commandName === `!mainkan` && context.username === `wiuwwiuw`) {
    client.say(target, `Pemenangnya adalah ${rollDice()}`);
  } else {
    console.log(`* Unknown command ${commandName}`);
  }
}
// Function called when the "dice" command is issued
function rollDice () {
return participants[Math.floor(Math.random() * participants.length)];
}
// Called every time the bot connects to Twitch chat
function onConnectedHandler (addr, port) {
  console.log(`* Connected to ${addr}:${port}`);
}