# expo-server-sdk-node ![Tests](https://github.com/expo/expo-server-sdk-node/workflows/Tests/badge.svg) [![codecov](https://codecov.io/gh/expo/expo-server-sdk-node/branch/master/graph/badge.svg)](https://codecov.io/gh/expo/expo-server-sdk-node)
Server-side library for working with Expo using Node.js.

If you have problems with the code in this repository, please file issues & bug reports at https://github.com/expo/expo. Thanks!

## Usage

_Note: the following code assumes that you are using JavaScript modules with `import`. If you aren't then you should use the old syntax for the SDK import: `const { Expo } = require('expo-server-sdk')`._

```bash
yarn add expo-server-sdk
```

```js
import { Expo } from 'expo-server-sdk';

// Create a new Expo SDK client
// optionally providing an access token if you have enabled push security
let expo = new Expo({
  accessToken: process.env.EXPO_ACCESS_TOKEN,
  useFcmV1: false // this can be set to true in order to use the FCM v1 API
});

// Create the messages that you want to send to clients
let messages = [];
for (let pushToken of somePushTokens) {
  // Each push token looks like ExponentPushToken[xxxxxxxxxxxxxxxxxxxxxx]

  // Check that all your push tokens appear to be valid Expo push tokens
  if (!Expo.isExpoPushToken(pushToken)) {
    console.error(`Push token ${pushToken} is not a valid Expo push token`);
    continue;
  }

  // Construct a message (see https://docs.expo.io/push-notifications/sending-notifications/)
  messages.push({
    to: pushToken,
    sound: 'default',
    body: 'This is a test notification',
    data: { withSome: 'data' },
  })
}

// The Expo push notification service accepts batches of notifications so
// that you don't need to send 1000 requests to send 1000 notifications. We
// recommend you batch your notifications to reduce the number of requests
// and to compress them (notifications with similar content will get
// compressed).
let chunks = expo.chunkPushNotifications(messages);
let tickets = [];
(async () => {
  // Send the chunks to the Expo push notification service. There are
  // different strategies you could use. A simple one is to send one chunk at a
  // time, which nicely spreads the load out over time:
  for (let chunk of chunks) {
    try {
      let ticketChunk = await expo.sendPushNotificationsAsync(chunk);
      console.log(ticketChunk);
      tickets.push(...ticketChunk);
      // NOTE: If a ticket contains an error code in ticket.details.error, you
      // must handle it appropriately. The error codes are listed in the Expo
      // documentation:
      // https://docs.expo.io/push-notifications/sending-notifications/#individual-errors
    } catch (error) {
      console.error(error);
    }
  }
})();

...

// Later, after the Expo push notification service has delivered the
// notifications to Apple or Google (usually quickly, but allow the service
// up to 30 minutes when under load), a "receipt" for each notification is
// created. The receipts will be available for at least a day; stale receipts
// are deleted.
//
// The ID of each receipt is sent back in the response "ticket" for each
// notification. In summary, sending a notification produces a ticket, which
// contains a receipt ID you later use to get the receipt.
//
// The receipts may contain error codes to which you must respond. In
// particular, Apple or Google may block apps that continue to send
// notifications to devices that have blocked notifications or have uninstalled
// your app. Expo does not control this policy and sends back the feedback from
// Apple and Google so you can handle it appropriately.
let receiptIds = [];
for (let ticket of tickets) {
  // NOTE: Not all tickets have IDs; for example, tickets for notifications
  // that could not be enqueued will have error information and no receipt ID.
  if (ticket.id) {
    receiptIds.push(ticket.id);
  }
}

let receiptIdChunks = expo.chunkPushNotificationReceiptIds(receiptIds);
(async () => {
  // Like sending notifications, there are different strategies you could use
  // to retrieve batches of receipts from the Expo service.
  for (let chunk of receiptIdChunks) {
    try {
      let receipts = await expo.getPushNotificationReceiptsAsync(chunk);
      console.log(receipts);

      // The receipts specify whether Apple or Google successfully received the
      // notification and information about an error, if one occurred.
      for (let receiptId in receipts) {
        let { status, message, details } = receipts[receiptId];
        if (status === 'ok') {
          continue;
        } else if (status === 'error') {
          console.error(
            `There was an error sending a notification: ${message}`
          );
          if (details && details.error) {
            // The error codes are listed in the Expo documentation:
            // https://docs.expo.io/push-notifications/sending-notifications/#individual-errors
            // You must handle the errors appropriately.
            console.error(`The error code is ${details.error}`);
          }
        }
      }
    } catch (error) {
      console.error(error);
    }
  }
})();

```

## Developing

The source code is in the `src/` directory and babel is used to turn it into ES5 that goes in the `build/` directory.

To build, `npm run build`.

To build and watch for changes, `npm run watch`.

## See Also

  * https://github.com/expo-community/expo-server-sdk-ruby
  * https://github.com/expo-community/expo-server-sdk-python