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

const mc = require('minecraft-protocol')

const options = {
  'online-mode': true
}

const server = mc.createServer(options)

server.on('login', function (client) {
  const addr = client.socket.remoteAddress
  console.log('Incoming connection', '(' + addr + ')')

  client.on('end', function () {
    console.log('Connection closed', '(' + addr + ')')
  })

  client.on('error', function (error) {
    console.log('Error:', error)
  })

  // send init data so client will start rendering world
  client.write('login', {
    entityId: client.id,
    levelType: 'default',
    gameMode: 0,
    dimension: 0,
    difficulty: 2,
    maxPlayers: server.maxPlayers,
    reducedDebugInfo: false
  })

  client.write('position', {
    x: 0,
    y: 1.62,
    z: 0,
    yaw: 0,
    pitch: 0,
    flags: 0x00
  })

  const msg = {
    translate: 'chat.type.announcement',
    'with': [
      'Server',
      'Hello, world!'
    ]
  }
  client.write('chat', {message: JSON.stringify(msg), position: 0})
})

server.on('error', function (error) {
  console.log('Error:', error)
})

server.on('listening', function () {
  console.log('Server listening on port', server.socketServer.address().port)
})