Step 10.1: Added counter for messages publication

Author: dotansimha

api/server/publications.ts

@@ -15,15 +15,18 @@ Meteor.publish('users', function(): Mongo.Cursor<User> {
   });
 });
 
-Meteor.publish('messages', function(chatId: string): Mongo.Cursor<Message> {
+Meteor.publish('messages', function(
+  chatId: string,
+  messagesBatchCounter: number): Mongo.Cursor<Message> {
   if (!this.userId || !chatId) {
     return;
   }
 
   return Messages.collection.find({
     chatId
   }, {
-    sort: { createdAt: -1 }
+    sort: { createdAt: -1 },
+    limit: 30 * messagesBatchCounter
   });
 });