Tutorial. How to create MIDI synthesizer with MIDI API and Node JS https://medium.com/nebo-15/tutorial-how-to-create-midi-synthesizer-with-midi-api-and-node-js-48d41c162009

midi-api_step7_server.js

stream.on('data', (data) => {
  console.log(data);
  const tone = data.readInt8(1);
  Object.keys(socket.clients).map(
    i => playTone(tone, socket.clients[i].createStream())
  );
});