async setup() {
    const waveletModule = await import('@ryohey/wavelet/dist/processor.js');
    const url = new URL(waveletModule.default, import.meta.url);
    await this.context?.audioWorklet.addModule(url);
  }

React.useEffect(() => {
   if (typeof window !== 'undefined') {
     const audioContext = new window.AudioContext();
     setRootStore(new RootStore(audioContext));
   }
 }, []);

export default class RootStore {
song: Song = emptySong();
readonly pianoRollStore!: PianoRollStore;
readonly controlStore!: ControlStore;
readonly player!: Player;
readonly synth!: SoundFontSynth;
readonly metronomeSynth!: SoundFontSynth;
readonly midiRecorder!: MIDIRecorder;

readonly trackMute = new TrackMute();
readonly historyStore = new HistoryStore<SerializedState>();
readonly rootViewStore = new RootViewStore();
readonly arrangeViewStore = new ArrangeViewStore(this);
readonly tempoEditorStore = new TempoEditorStore(this);
readonly midiDeviceStore = new MIDIDeviceStore();
readonly exportStore = new ExportStore();
readonly authStore = new AuthStore();
readonly cloudFileStore = new CloudFileStore(this);
readonly settingStore = new SettingStore();
readonly synthGroup = new GroupOutput();
readonly midiInput = new MIDIInput();
readonly soundFontStore!: SoundFontStore;

constructor(audioContext: AudioContext) {
  makeObservable(this, {
    song: observable.ref,
  });
  if (typeof window !== 'undefined') {
    this.synth = new SoundFontSynth(audioContext);
    this.metronomeSynth = new SoundFontSynth(audioContext);
    this.synthGroup.outputs.push({ synth: this.synth, isEnabled: true });
    this.player = new Player(this.synthGroup, this.metronomeSynth, this.trackMute, this);

    this.midiRecorder = new MIDIRecorder(this.player, this);

    this.pianoRollStore = new PianoRollStore(this);
    this.controlStore = new ControlStore(this.pianoRollStore);
    this.soundFontStore = new SoundFontStore(this.synth);

    const preview = previewMidiInput(this);

    this.midiInput.onMidiMessage = (e: any) => {
      preview(e);
      this.midiRecorder.onMessage(e);
    };

    this.pianoRollStore!.setUpAutorun();
    this.arrangeViewStore.setUpAutorun();
    this.tempoEditorStore.setUpAutorun();

    registerReactions(this);

    this.init();
  }
}

private async init() {
  try {
    await this.synth.setup();
    await this.soundFontStore.init();
    this.setupMetronomeSynth();
  } catch (e) {
    console.log(e);
    this.rootViewStore.initializeError = e as Error;
    this.rootViewStore.openInitializeErrorDialog = true;
  }
}

...
}