How can I resolve the missing sendMulticast method in Firebase-admin Messaging for Node.js?

It appears you’re getting a type error because the Messaging instance you’re using doesn’t include a sendMulticast method. This usually means that your firebase‑admin package (or its TypeScript definitions) is out‑of‑date or misconfigured. In recent versions of the Firebase Admin SDK for Node.js, a method to send multicast messages is available—similar in spirit to the SendMulticastAsync methods documented for the .NET SDK. For example, with an up‑to‑date SDK the code would look like this:

JAVASCRIPTCopied
import admin from 'firebase-admin';

admin.initializeApp();

const multicastMessage = {
  tokens: [/* Array of device tokens */],
  notification: {
    title: 'FCM Message',
    body: 'This is an FCM notification message!'
  }
};

admin.messaging().sendMulticast(multicastMessage)
  .then((response) => {
    console.log(`${response.successCount} messages were sent successfully`);
  })
  .catch((error) => {
    console.error('Error sending messages:', error);
  });

Steps to resolve the error:

1. Check your firebase‑admin version:
   Ensure that you’re using a version that supports multicast messaging. If you’re on an earlier version, update your package:

   BASHCopied
   npm install firebase-admin@latest

2. Verify TypeScript definitions:
   If you’re using TypeScript, make sure the type definitions installed along with firebase‑admin are up‑to‑date. An outdated type file could result in a missing sendMulticast method even when the runtime supports it.

3. Alternative methods if needed:
   If for some reason you cannot update, consider using alternative methods such as sending messages individually or via sendToDevice (suitable for sending a message to multiple tokens in one call) as supported by your version.

By taking these steps, your Messaging instance should recognize sendMulticast, letting you successfully send your multicast notifications.