setUpNotifications.js

import { Notifications } from 'expo'
import { Platform } from 'react-native'
import * as Permissions from 'expo-permissions'
import Constants from 'expo-constants'

// const PUSH_ENDPOINT = 'https://your-server.com/users/push-token'

function registerForPushNotificationsAsync() {
  // eslint-disable-next-line no-async-promise-executor
  return new Promise(async (resolve, reject) => {
    if (!Constants.isDevice) reject(new Error('not a real device'))
    try {
      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') {
        reject(new Error('no permission'))
      }

      const token = await Notifications.getExpoPushTokenAsync()
      resolve(token)
    } catch (e) {
      reject(new Error('no permission'))
    }
  })
}

export function dismissNotifications() {
  if (Platform.OS === 'ios') {
    Notifications.setBadgeNumberAsync(0)
  } else {
    Notifications.dismissAllNotificationsAsync()
  }
}

export function createAndroidNotificationChanel() {
  if (Platform.OS === 'android') {
    try {
      Notifications.createChannelAndroidAsync('new-posts', {
        name: 'New posts',
        sound: true,
      })
    } catch (e) {
      console.log('err createAndroidNotificationChanel', e)
    }
  }
}

export default registerForPushNotificationsAsync