How to use the @tonejs/midi.Midi function in @tonejs/midi

function createMidi(name: string, notes: INote[], instrument: Instrument) {
  const midi = new MIDI();

  const tracks = midi.addTrack();
  const { name: instrumentName, group } = instrument;

  notes.forEach(_note => tracks.addNote(_note));

  const duration = tracks.duration;

  // @ts-ignore
  const midiJson: Midi = midi.toJSON();

  return {
    ...midiJson,
    header: {
      ...midiJson.header,
      name

files.forEach(file => {
    const data = fs.readFileSync(
      path.resolve(__dirname, "../public/static/midi", file)
    );
    const { header, duration, tracks } = new Midi(data);
    meta.push({
      url: `/static/midi/${file}`,
      label: header.name || file.replace(".mid", ""),
      duration,
      tracks: tracks.length
    });
  });