App.js

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

import CustomComponent from './Component';

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 30,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
    fontSize: 35,
  },
});

const instructions = Platform.select({
  ios: 'iOS Device',
  android: 'Android Platform',
});

export default class App extends Component {
  constructor() {
    super();
    this.state = {};
  }

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.welcome}>
          React Native! {Platform.OS}
        </Text>
        <Text style={styles.instructions}>
          To get started, edit App.js
        </Text>
        <Text style={styles.instructions}>
          {instructions}
        </Text>
        <CustomComponent platform={Platform.OS} />
      </View>
    );
  }
}