App.js

import Constants from 'expo-constants';
import * as Notifications from 'expo-notifications';
import React, { Component } from 'react';
import { Text, View, Button, Platform, Alert } from 'react-native';

Notifications.setNotificationHandler({
  handleNotification: async () => ({
    shouldShowAlert: true,
    shouldPlaySound: false,
    shouldSetBadge: false,
  }),
});


export default class App extends Component {

  state = {
    expoPushToken: '',
    notification: false
  }


  componentDidMount() {
    this.registerForPushNotificationsAsync().then(token => this.setState({expoPushToken: token}))

    this.notificationListener = Notifications.addNotificationReceivedListener(notification => {
      this.setState({notification})
    });

    this.responseListener = Notifications.addNotificationResponseReceivedListener(response => {
      console.log(response);
    });
  }


  componentWillUnmount() {
    Notifications.removeNotificationSubscription(this.notificationListener);
    Notifications.removeNotificationSubscription(this.responseListener);
  }


  render() {
    const {expoPushToken, notification} = this.state

    return (
      <View
        style={{
          flex: 1,
          alignItems: 'center',
          justifyContent: 'space-around',
        }}>
        <Text>Your expo push token: {expoPushToken}</Text>
        <View style={{ alignItems: 'center', justifyContent: 'center' }}>
          <Text>Title: {notification && notification.request.content.title} </Text>
          <Text>Body: {notification && notification.request.content.body}</Text>
          <Text>Data: {notification && JSON.stringify(notification.request.content.data)}</Text>
        </View>
        <Button
          title="Press to Send Notification"
          onPress={async () => {
            await this.sendPushNotification(expoPushToken);
          }}
        />
      </View>
    )
  }

  // Can use this function below, OR use Expo's Push Notification Tool-> https://expo.io/notifications
  sendPushNotification = async (expoPushToken) => {
    console.log('Trying to send PN')
    const message = {
      to: expoPushToken,
      sound: 'default',
      title: 'Original Title',
      body: 'And here is the body!',
      data: { someData: 'goes here' },
    };

    await fetch('https://exp.host/--/api/v2/push/send', {
      method: 'POST',
      headers: {
        Accept: 'application/json',
        'Accept-encoding': 'gzip, deflate',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(message),
    });
  }

  registerForPushNotificationsAsync = async () => {
    let token;
    if (Constants.isDevice) {
      const { status: existingStatus } = await Notifications.getPermissionsAsync();
      let finalStatus = existingStatus;
      if (existingStatus !== 'granted') {
        const { status } = await Notifications.requestPermissionsAsync();
        finalStatus = status;
      }
      if (finalStatus !== 'granted') {
        alert('Failed to get push token for push notification!');
        return;
      }
      token = (await Notifications.getExpoPushTokenAsync()).data;
      console.log(token);
    } else {
      alert('Must use physical device for Push Notifications');
    }

    if (Platform.OS === 'android') {
      Notifications.setNotificationChannelAsync('default', {
        name: 'default',
        importance: Notifications.AndroidImportance.MAX,
        vibrationPattern: [0, 250, 250, 250],
        lightColor: '#FF231F7C',
      });
    }

    return token;
  }
}