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

const mc = require('minecraft-protocol')

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

const customPackets = {
  1.8: {
    play: {
      toClient: {
        types: {
          packet_custom_name: [
            'container', [
              {
                name: 'age',
                type: 'i64'
              },
              {
                name: 'time',
                type: 'i64'
              }
            ]
          ],
          packet: [
            'container',
            [
              {
                name: 'name',
                type: [
                  'mapper',
                  {
                    type: 'varint',
                    mappings: {
                      '0x7A': 'custom_name'
                    }
                  }
                ]
              },
              {
                name: 'params',
                type: [
                  'switch',
                  {
                    compareTo: 'name',
                    fields: {
                      custom_name: 'packet_custom_name'
                    }
                  }
                ]
              }
            ]
          ]
        }
      }
    }
  }
}

const client = mc.createClient({
  host: process.argv[2],
  port: parseInt(process.argv[3]),
  username: process.argv[4] ? process.argv[4] : 'echo',
  password: process.argv[5],
  customPackets: customPackets
})

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('login', function () {
  client.deserializer.write(Buffer.from('7A0000000000909327fffffffffffffc18', 'hex'))
  console.log('login')
})

client.on('custom_name', function (packet) {
  console.log(packet)
})