title: (React-Native) Possible Unhandled Promise Rejection FBSDK
body: <p>So I have this code:</p>
  
  <pre><code>export default class Login extends Component {
  
    constructor(props){
      super(props);
      this._fbAuth = this._fbAuth.bind(this);
      this.login = this.login.bind(this);
    }
  
    login(){
        this.props.navigator.push({
          id: "Home",
        });
    }
  
    _fbAuth(){
      LoginManager.logInWithReadPermissions(['public_profile']).then(
        function(result) {
          if (result.isCancelled) {
            alert('Login cancelled');
          } else {
  alert('Login success with permissions: '+result.grantedPermissions.toString());
            this.login();
          }
        },
        function(error) {
          alert('Login fail with error: ' + error);
        }
      );
    }
  
    render() {
      return (
        &lt;View style={styles.container}&gt;
                &lt;View style={styles.botbuttoncontainer}&gt;
                  &lt;Text style={styles.otherlogintext}&gt;Or log in using&lt;/Text&gt;
                  &lt;View style={styles.otherloginbutton}&gt;
                  &lt;TouchableOpacity style={styles.facebookbutton} activeOpacity={0.5} onPress={()=&gt;this._fbAuth()}&gt;
                    &lt;Icons name="logo-facebook" size={20} color="white"/&gt;
                  &lt;/TouchableOpacity&gt;
                  &lt;TouchableOpacity style={styles.twitterbutton} activeOpacity={0.5}&gt;
                    &lt;Icons name="logo-twitter" size={20} color="white"/&gt;
                  &lt;/TouchableOpacity&gt;
                  &lt;TouchableOpacity style={styles.googlebutton} activeOpacity={0.5}&gt;
                    &lt;Icons name="logo-googleplus" size={20} color="white"/&gt;
                  &lt;/TouchableOpacity&gt;
                  &lt;/View&gt;
                &lt;/View&gt;
        &lt;/View&gt;
      );
    }
  }
  </code></pre>
  
  <p>Every time I try to login with facebook it's successful. but I always get a warning says </p>
  
  <blockquote>
    <p>"Possible Unhandled Promise Rejection(id:0): TypeError: undefined is
    not a function (evaluating 'this.login()')"</p>
  </blockquote>
  
  <p>I try to bind both function <code>_fbAuth</code> and login on constructor but it's still give the same warning.</p>