Step 13.33: Add hook for removing unused messages

Author: dotansimha

api/server/collections/chats.ts

@@ -1,4 +1,10 @@
 import { MongoObservable } from 'meteor-rxjs';
 import { Chat } from '../models';
+import { Messages } from './messages';
 
 export const Chats = new MongoObservable.Collection<Chat>('chats');
+
+// Dispose unused messages
+Chats.collection.after.remove(function (userId, doc) {
+  Messages.collection.remove({ chatId: doc._id });
+});