title: Async storage not working to set or get on React Native
body: <p>Im trying to make the user authentication using async storage to decide which screen will be rendered so when i get the data from the async storage returns to me undefined can someone help me?</p>
  
  <p>My get code:</p>
  
  <pre><code>var login;
  AsyncStorage.getItem("login").then((value) =&gt; {
        login = value;
  }).done();
  alert(login);
  </code></pre>
  
  <p>My set code:</p>
  
  <pre><code>const insert_user = (username) =&gt; {
    AsyncStorage.setItem("login", username);
    Toast.show({
      supportedOrientations: ['portrait', 'landscape'],
      text: `User registered with success`,
      position: 'bottom',
      buttonText: 'Dismiss'
    });
  }
  </code></pre>