Adding the notifications code

App.js

import React from 'react';
import {SafeAreaView, StyleSheet, View, Text, StatusBar, TouchableOpacity, Platform} from 'react-native';
import Notifications from './NotificationService'

class App extends React.Component {
  constructor(props) {
    super(props);
    Notifications.init(this.handleRegister);
  }
  
  handleRegister = token => {
    console.log('Device Token Received ', token)
    // Make your API call to save the token here
  }
  
  componentDidMount() {
    Notifications.listen(notification => console.log('do what you need to do', notification);
  }
  
  componentWillUnmount() {
    Notifications.delete();
  }

  render() {
    return (
      <>
        <StatusBar barStyle="dark-content" />
        <SafeAreaView style={styles.body}>
          <TouchableOpacity
            accessibilityRole={'button'}
            onPress={this.handleNotificationPressWithDelay(10000)}
            style={styles.linkContainer}>
            <Text style={styles.link}>Notification in 10 seconds</Text>
          </TouchableOpacity>
          <View style={styles.separator} />
          <TouchableOpacity
            accessibilityRole={'button'}
            onPress={this.handleNotificationPressWithDelay(0)}
            style={styles.linkContainer}>
            <Text style={styles.link}>Notification now</Text>
          </TouchableOpacity>
        </SafeAreaView>
      </>
    );
  }
}

// styles in https://github.com/arnaudambro/push-notifications-test/blob/master/front/App.js

export default App;