PushNotification.js

import { Permissions, Notifications } from 'expo';
import { BASE_URL } from './Constants';

const PUSH_ENDPOINT = `${BASE_URL}/push-token`;

export async function registerForPushNotificationsAsync() {
  const { status: existingStatus } = await Permissions.getAsync(
    Permissions.NOTIFICATIONS
  );
  let finalStatus = existingStatus;

  // only ask if permissions have not already been determined, because
  // iOS won't necessarily prompt the user a second time.
  if (existingStatus !== 'granted') {
    // Android remote notification permissions are granted during the app
    // install, so this will only ask on iOS
    const { status } = await Permissions.askAsync(Permissions.NOTIFICATIONS);
    finalStatus = status;
  }

  // Stop here if the user did not grant permissions
  if (finalStatus !== 'granted') {
    return;
  }

  // Get the token that uniquely identifies this device
  let expoPushToken = await Notifications.getExpoPushTokenAsync();
  return expoPushToken;

  // POST the token to your backend server from where you can retrieve it to send push notifications.
  // return fetch(PUSH_ENDPOINT, {
  //   method: 'POST',
  //   headers: {
  //     Accept: 'application/json', 
  //     'Content-Type': 'application/json',
  //   },
  //   body: JSON.stringify({
  //     token: expoPushToken,
  //     helpRequesterId: '',
  //   }),
  // });
}