React Native Redux: Error Can't find variable mapStateToProps

import React, { Component } from 'react';
import ReactNative from 'react-native';
import { AppRegistry,Text,View,} from 'react-native';
import { Button } from 'react-native-elements'
import { StackNavigator } from 'react-navigation'
import store from '../store/store';
import { Provider,connect } from  'react-redux';
import Register1 from './emailandpass'
import Register2   from './namefields'
//import login      from './login'
//import confirmation from './confirmation'
//import success      from './success'

class Loginscreen extends React.Component{
 static navigationOptions= {
  title: 'Welcome to LearnD',
        }
  render() {
   const { navigate  } = this.props.navigation;
    return(
      <Provider store={store}> 
      <View>
      <Text>Have you got an account ?</Text>
      <Button
        onPress={()=> navigate('Register1')}
        title="Register here !"
        />
      </View>
      </Provider> 

    );
  }
};

const App = StackNavigator({
  Home: { screen: Loginscreen},
  Register1: {screen: Register1  },
  Register2: {screen: Register2}
});

export default connect(mapStateToProps)(Landingscreen);