Ionic2 Storage data persistence


hello, I am considering utilizing the ionic 2 storage facility for data persistence.

normally, we need a mechanism to check if a data is existing before initializing the data in persistant storage; something similar to this:

constructor(platform: Platform,  private storage: Storage) {
    platform.ready().then(() => {
      //make sure the key does not exist in persistence
      if(!'key')){'key', 'initial value');

without this, we just kept overwriting previous settings.
I read the docs about Storage, and did not find anything relevant…

anyone has any idea?