The MIDIMessageEvent interface of the Web MIDI API represents the event passed to the midimessage event of the MIDIInput interface. A midimessage event is fired every time a MIDI message is sent from a device represented by a MIDIInput, for example when a MIDI keyboard key is pressed, a knob is tweaked, or a slider is moved.

MIDIMessageEvent()

Creates a new MIDIMessageEvent object instance.

This interface also inherits properties from Event.

MIDIMessageEvent.data

A Uint8Array containing the data bytes of a single MIDI message. See the MIDI specification for more information on its form.

This interface doesn't implement any specific methods, but inherits methods from Event.

The following example prints all MIDI messages to the console.

navigator.requestMIDIAccess().then((midiAccess) => {
  Array.from(midiAccess.inputs).forEach((input) => {
    input[1].onmidimessage = (msg) => {
      console.log(msg);
    };
  });
});