App.js

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 * @flow
 */

import { MobileAppBridge } from 'NativeModules';
import React, { Component } from 'react';
import {
  Platform,
  StyleSheet,
  Text,
  View
} from 'react-native';

const instructions = Platform.select({
  ios: 'Press Cmd+R to reload,\n' +
    'Cmd+D or shake for dev menu',
  android: 'Double tap R on your keyboard to reload,\n' +
    'Shake or press menu button for dev menu',
});

async function displayHelloWorld(self) {
  try {
    console.log("mrpotato");
    let text = await MobileAppBridge.sayHelloWorld("Android");
      self.setState({
        hello: text
      });
  } catch (e) {
    console.log(e);
  }
}

type Props = {};
export default class App extends Component<Props> {

  state = {}

  componentDidMount() {
    displayHelloWorld(this);
  }

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.welcome}>
          Welcome to React Native!
	  rust says: {this.state.hello}
        </Text>
        <Text style={styles.instructions}>
          To get started, edit App.js
        </Text>
        <Text style={styles.instructions}>
          {instructions}
        </Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});