MyController.midiMap = {
    {channel: 1, status: 0x90, control: Channel1.play, type: 'button'}
}

// The below would not need to be explicitly specified by the mapping; it would be the default MIDI receive behavior for all objects with a type attribute equal to 'button'.
Channel1.play.MyController.receive = function (velocity) {
    if (velocity) {
        this.value = ! this.value // what would be proper JS way to access Channel1.play.value?
    }
}

Channel1.play = { midi: { input: { MyController: {channel: 1, status, 0x90} }, output: this.input } }
// Also could be written as:
Channel1.play = {
    input:
        midi: {
            MyController: {
                channel: 1,
                status: 0x90
            }
        },
    output: this.input // Send output with same channel & status with value determined by return value of the send method below
}

Object.defineProperties(Channel1.play.output.midi.MyController, {
    get send () {
        if (this.value) { // What would be proper JS to reference Channel1.play.value here?
            return colorCode['green']
        }
        return colorCode['red']
    }
})

Channels[1].controls = [
  MIDI.button([1, 1], 'mixer.kill.hi',  1, 'toggle'),
  MIDI.button([1, 2], 'mixer.kill.mid', 1, 'toggle'),
  MIDI.button([1, 3], 'mixer.kill.lo',  1, 'toggle'),
  
  MIDI.linear([1, 16], 'mixer.eq.hi'),
  MIDI.linear([1, 17], 'mixer.eq.mid'),
  MIDI.linear([1, 18], 'mixer.eq.lo'),
  
  MIDI.encoder( ... ),
  
  OSC.handler('/address/foo', function (...) { ... }),
  
  HID.handler( ... )
];

Events = new EventEmitter();
Events.on('mixer.kill.hi', function (channel, value) {
  if (value === 'toggle') {
    Channels[channel].hiKill = !Channels[channel].hiKill;
  } else if (value === true || value === false) {
    Channels[channel].hiKill = value
  } else {
    // throw error?
  }
});

MIDI = {
  button: function (mask, event /* + optional arg1, arg2 ... argN */) {
    var args = [].slice.call(arguments, 2); // gets list of optional arguments
    return function buttonPressed (midiMessage) {
      if (midiMessage.matches(mask)) {
        Events.emit.apply(Events, [event].concat(args))
        // that was a fancy way of saying `Events.emit(event, arg1, arg2 ... argN)`+
      }
    }
  },
  linear: function (mask, event) {
    var args = [].slice.call(arguments, 2); // gets list of optional arguments
    return function potRotated (midiMessage) {
      if (midiMessage.matches(mask)) {
        Events.emit.apply(Events, [event].concat(args).concat([midiMessage.data2]));
      }
    }
  }
}

// at the top of the chain sits a function which
// simply runs every received MIDI message through
// every registered MIDI handler.
Events.on('midi.input', function (midiMessage) {
  Channel1.controls.map(function (control) { control(midiMessage); });
});