title: React Native Get Async Storage return Unhandled Promise
body: <p>Right now I want to save user token after the user login successful.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>onPress(){
    return axios.post('https://api.example.net/v1/user/auth/login', {
      email: this.state.email,
      password: this.state.password,
    }, {
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
      },
    }).then((response) =&gt; {
      AsyncStorage.setItem('token', response.data.login._cxz, () =&gt; {
        console.log('success');
      });
      this.props.navigator.immediatelyResetRouteStack([{name: 'tweets'}]);
    })
      .catch((error) =&gt; {
        this.setState({errorMessage: error.response.data.message});
    });
  }
  </code></pre>
  
  <p>I already make sure that <code>response.data.login._cxz</code> has a value.
  Right until here is working. the login will redirect me to <code>tweets</code> route.</p>
  
  <p>On my tweets.js:</p>
  
  <pre><code>  constructor(props){
      super(props);
      this.state({token : ''});
    }
    componentWillMount() {
      AsyncStorage.getItem('token', (err, value) =&gt; {
  
        console.log(value);
      })
    }
  </code></pre>
  
  <p>I just simple <code>console.log</code> it to view if the token is saved or not.
  But everytime login is done (the success log is appear). I always got this error when enter my tweets:</p>
  
  <p><a href="https://i.stack.imgur.com/bhm9a.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bhm9a.png" alt="error"></a></p>
  
  <p>Any solution?</p>
  
  <p>Thanks.</p>