async function destroyWindowIpcExecutor(win) {
  win.destroy();
}

async function openFileDialogIpcExecutor(win) {
  const result = await dialog.showOpenDialog(win, {
    properties: ["openFile", "multiSelections"]
  });

  return {
    path: result.filePaths
  };
}

async function readFileIpcExecutor(win, context, path) {
  const file = await fsp.readFile(path, { encoding: "utf8" });

  win.title = path.split("/").pop();
  return {
    content: JSON.parse(file)
  };
}

const mapping = {
  DESTROY_WINDOW: destroyWindowIpcExecutor,
  OPEN_FILE_DIALOG: openFileDialogIpcExecutor,
  READ_FILE: readFileIpcExecutor
};

const ipcController = new IpcController(mapping);

const win = new BrowserWindow({
  // ...
  webPreferences: {
    // ...
    preload: path.join(__dirname, "preload.js")
  }
});
ipcController.setupIpcListeners(win);

contextBridge.exposeInMainWorld("electron", {
  closeWindow: async () => {
    await Ipc.trigger("DESTROY_WINDOW");
  },

  openFileDialog: async () => {
    return await Ipc.call("OPEN_FILE_DIALOG");
  },

  readFile: async (path) => {
    return await Ipc.call("READ_FILE", path);
  }
});

const { electron } = window;

electron.closeWindow();

const { path } = await electron.openFileDialog();

const { content } = await electron.readFile("/path/to/file");

class MyCustomObject {
  custom(param) {
    return `custom ${param}`;
  }

  test() {
    return "test";
  }
}

const mapping = {
  ...,
  MY_CUSTOM_OBJECT_PROXY: Ipc.delegate(new MyCustomObject())
};

const ipcController = new IpcController(mapping);

const win = new BrowserWindow({
  // ...
  webPreferences: {
    // ...
    preload: path.join(__dirname, "preload.js")
  }
});
ipcController.setupIpcListeners(win);

contextBridge.exposeInMainWorld("electron", {
  ...,
  
  myCustomObject: Ipc.proxy("MY_CUSTOM_OBJECT_PROXY", {
    custom: () => {},
    test: () => {}
  })
});

const { electron } = window;

const customResponse = await electron.myCustomObject.custom(param);
const testResponse = await electron.myCustomObject.test();