node-minecraft-protocol/examples/client_chat/client_chat.js

const mc = require('minecraft-protocol')
const readline = require('readline')
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false,
  prompt: 'Enter a message> '
})

const [,, host, port, username] = process.argv
if (!host || !port) {
  console.error('Usage: node client_chat.js <host> <port> <username>')
  console.error('Usage (offline mode): node client_chat.js <host> <port> offline')
  process.exit(1)
}

const client = mc.createClient({
  host,
  port,
  username,
  auth: username === 'offline' ? 'offline' : 'microsoft'
})

// Boilerplate
client.on('disconnect', function (packet) {
  console.log('Disconnected from server : ' + packet.reason)
})

client.on('end', function () {
  console.log('Connection lost')
  process.exit()
})

client.on('error', function (err) {
  console.log('Error occurred')
  console.log(err)
  process.exit(1)
})

client.on('connect', () => {
  const ChatMessage = require('prismarine-chat')(client.version)

  console.log('Connected to server')
  rl.prompt()

  client.on('playerChat', function ({ senderName, message, formattedMessage, verified }) {
    const chat = new ChatMessage(formattedMessage ? JSON.parse(formattedMessage) : message)
    console.log(senderName, { true: 'Verified:', false: 'UNVERIFIED:' }[verified] || '', chat.toAnsi())
  })
})

// Send the queued messages
const queuedChatMessages = []
client.on('state', function (newState) {
  if (newState === mc.states.PLAY) {
    queuedChatMessages.forEach(message => client.chat(message))
    queuedChatMessages.length = 0
  }
})

// Listen for messages written to the console, send them to game chat
rl.on('line', function (line) {
  if (line === '') {
    return
  } else if (line === '/quit') {
    console.info('Disconnected from ' + host + ':' + port)
    client.end()
    return
  } else if (line === '/end') {
    console.info('Forcibly ended client')
    process.exit(0)
  }
  if (!client.chat) {
    queuedChatMessages.push(line)
  } else {
    client.chat(line)
  }
})