const Expo = require('expo-server-sdk')
const expo = new Expo()

async function send(messages) {
  const chunks = expo.chunkPushNotifications(messages)
  for (const chunk of chunks) {
    try {
      const receipts = await expo.sendPushNotificationsAsync(chunk)
      receipts.forEach(receipt => {
        if (receipt.status === 'error') {
          throw new Error(receipt.message)
        }
      })
    } catch (error) { ... }
  }
}