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

const mc = require('minecraft-protocol')

if (process.argv.length < 4 || process.argv.length > 6) {
  console.log('Usage : node echo.js <host> <port> [<name>]')
  process.exit(1)
}

const client = mc.createClient({
  host: process.argv[2],
  port: parseInt(process.argv[3]),
  username: process.argv[4] ? process.argv[4] : 'echo'
})
client.on('error', function (err) {
  console.error(err)
})

client.on('connect', function () {
  console.info('connected')
})
client.on('disconnect', function (packet) {
  console.log('disconnected: ' + packet.reason)
})
client.on('end', function () {
  console.log('Connection lost')
})
client.on('chat', function (packet) {
  const jsonMsg = JSON.parse(packet.message)
  if (jsonMsg.translate === 'chat.type.announcement' || jsonMsg.translate === 'chat.type.text') {
    const username = jsonMsg.with[0].text
    const msg = jsonMsg.with[1]
    if (username === client.username) return
    if (msg.text) client.write('chat', { message: msg.text })
    else client.write('chat', { message: msg })
  }
})