MIDI to OSC

midi2osc.js

const midi = require('midi');
const { Client } = require('node-osc');

const MIDI_INPUT = 1;
const ADDRESS = 'localhost';
const PORT = 8886;

class MIDI2OSC {
  constructor(midiInput=MIDI_INPUT, address=ADDRESS, port=PORT) {
    this.client = new Client(address, port);
    this.input = new midi.input();

    this.inputCount = this.input.getPortCount();
    this.inputName = this.input.getPortName(midiInput);
    this.input.openPort(midiInput);
    this.input.on('message', (delta, message) => {
      this.send(message);
    });
    
    console.log('Found inputs:');
    for (let i = 0; i < this.inputCount; i++) {
      console.log(`${this.input.getPortName(i)}${i === midiInput ? ' [selected]' : ''}`)
    }
  }

  send(data) {
	  console.log(data);
    const oscData = this.midiToOsc(data);
    if (oscData) {
      const [command, value] = oscData;
      console.log(`Sending: dirtgl/${command}:${value}`);
      this.client.send(`dirtgl/${command}`, value);
    }
  }

  /**
   * Maps midi commands from LaunchControl to OSC address/value,
   * device-configuration specific.
   */
  midiToOsc(data) {
    const [status, data1, data2] = data;
    const channel = status & 0b00001111;
    const message = status >> 4;
    let type;
    switch (message) {
      case 8: type = 'noteOff'; break; 
      case 9: type = 'noteOn'; break; 
      case 10: type = 'keyPressure'; break; 
      case 11: type = 'controlChange'; break; 
      case 12: type = 'programChange'; break; 
      case 13: type = 'channelPressure'; break; 
      case 14: type = 'pitchBend'; break; 
      default: type = `UNKNOWN-${message}`;
    }

    // https://users.cs.cf.ac.uk/Dave.Marshall/Multimedia/node158.html
 
    let command = null;
    let value = null;

    if (type === 'controlChange') {
      const note = data1;
      value = data2;
    
      if (note >= 13 && note <= 20) {
        command = `send-a/${note - 13}`;
      } else if (note >= 29 && note <= 36) {
        command = `send-b/${note - 29}`;
      } else if (note >= 49 && note <= 56) {
        command = `pan/${note - 49}`;
      } else if (note >= 77 && note <= 84) {
        command = `fader/${note - 77}`;
      }
    }
    else if (type === 'noteOn') {
      const note = data1;
      //const value = data2;

      if ((note >= 41 && note <= 44) ||
          (note >= 57 && note <= 60)) {
        value = note > 44 ? (note - 57 + 4) : note - 41;
        command = `scene-select`;
      } else if ((note >= 73 && note <= 76) ||
          (note >= 89 && note <= 92)) {
        value = note > 76 ? (note - 89 + 4) : note - 73;
        command = `execute`;
      }
    }

    return command != null && value != null ? [command, value] : null; 
  }
}
const converter = new MIDI2OSC();