function rejectWithMessage(error) {
  return Promise.reject(error.message);
}
This is a modified version of redux-storage-engine-electron-store
(https://github.com/collmot/redux-storage-engine-electron-store)

This fork does two things:
- Exposes the created Electron store on the `window`, for debugging
- Simplifies a bit by assuming a `key` will be provided, and no
  modifications to the store are required.