title: React Native + TypeScript, can't set State
body: <p>I know my functioning is running but for whatever reason I can't set the state of this property "isLoggedIn"</p>
  
  <p>In the componentDidMount() I setState based on login detection and it doesn't seem to work.</p>
  
  <pre><code>import React, {
     Component
  } from 'react';
  import { AppRegistry, View, StyleSheet, Text } from 'react-native';
  import { Actions } from 'react-native-router-flux';
  
  import Firestack from 'react-native-firestack';
  
  const firestack = new Firestack();
  
  interface Props {
     isLoggedIn?: boolean;
  }
  
  interface State {
     isLoggedIn: boolean;
  }
  
  
  export default class MainList extends Component&lt;Props, State&gt; {
  
      state = {
        isLoggedIn: false,
      };
  
      constructor(props: any) {
  
         super(props);
         console.log("Is anyone logged in?: " + this.isLoggedIn);
  
      }
  
      isLoggedIn = this.state.isLoggedIn;
  
      componentDidMount() {
  
        firestack.auth.listenForAuth((evt: any) =&gt; {
        // evt is the authentication event
        // it contains an `error` key for carrying the
        // error message in case of an error
        // and a `user` key upon successful authentication
  
          if (!evt.authenticated) {
          // There was an error or there is no user
          //console.error(evt.error);
  
          this.setState({isLoggedIn: false});
          console.log("The state of isLoggedIn is: " + this.isLoggedIn);
  
          } else {
          // evt.user contains the user details
          console.log('User details', evt.user);
  
          this.setState({isLoggedIn: true});
          console.log("The state of isLoggedIn is: " + this.isLoggedIn);
  
          }
  
          if (!this.isLoggedIn) {
  
              Actions.welcome();
  
          }
  
  
      }); 
  
  }
  
  render() {
  
      return (
          &lt;View style={styles.View}&gt;
  
              &lt;Text style={styles.textLabel}&gt;The main view&lt;/Text&gt;
  
          &lt;/View&gt;
         )
  
       }
  
    }
  
  const styles = StyleSheet.create({
  
      View: {
         padding: 20
      },
     textLabel: {
      fontSize: 20,
      marginBottom: 10,
      height: 20
    },
  textInput: {
      height: 20,
      fontSize: 15,
      marginBottom: 20
  }
  
   });
  
   AppRegistry.registerComponent('MainList', ()=&gt; MainList);
  </code></pre>
  
  <p>Anything that I'm doing wrong?</p>