App.js

import Constants from "expo-constants";
import * as Notifications from "expo-notifications";
import * as Permissions from "expo-permissions";
import React, { useState, useEffect, useRef } from "react";
import { Text, View, Button, Platform } from "react-native";

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

// This listener is fired whenever a user taps on or interacts with a notification (works when app is foregrounded, backgrounded, or killed)
Notifications.addNotificationResponseReceivedListener((response) => {
  alert(JSON.stringify(response));
});

export default function App() {
  const [expoPushToken, setExpoPushToken] = useState("");
  const [notification, setNotification] = useState(false);
  const notificationListener = useRef();
  const responseListener = useRef();

  useEffect(() => {
    registerForPushNotificationsAsync().then((token) =>
      setExpoPushToken(token)
    );

    return () => {
      Notifications.removeAllNotificationListeners();
    };
  }, []);

  return (
    <View
      style={{
        flex: 1,
        alignItems: "center",
        justifyContent: "space-around",
      }}
    >
      <Text>Your expo push token: {expoPushToken}</Text>
      <View style={{ alignItems: "center", justifyContent: "center" }}>
        <Text>Press the button below and kill your app</Text>
      </View>
      <Button
        title="Press to Send Notification"
        onPress={async () => {
          await sendPushNotification(expoPushToken);
        }}
      />
    </View>
  );
}

// Can use this function below, OR use Expo's Push Notification Tool-> https://expo.io/dashboard/notifications
async function sendPushNotification(expoPushToken) {
  await Notifications.scheduleNotificationAsync({
    content: {
      title: "1 You've got mail! 📬",
      subtitle: "this is the sub",
      body: "What would you like to do with it?",
      vibrate: false,
    },
    trigger: { seconds: 5 },
  });
}

async function registerForPushNotificationsAsync() {
  let token;
  if (Constants.isDevice) {
    const { status: existingStatus } = await Permissions.getAsync(
      Permissions.NOTIFICATIONS
    );
    let finalStatus = existingStatus;
    if (existingStatus !== "granted") {
      const { status } = await Permissions.askAsync(Permissions.NOTIFICATIONS);
      finalStatus = status;
    }
    if (finalStatus !== "granted") {
      alert("Failed to get push token for push notification!");
      return;
    }
    token = (
      await Notifications.getExpoPushTokenAsync({
        experienceId: "@charliecruzan/myapp",
      })
    ).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;
}