Step 6.3: Define 'addChat' Method

api/server/methods.ts

@@ -10,6 +10,28 @@ const nonEmptyString = Match.Where((str) => {
 
 export function initMethods() {
   Meteor.methods({
+    addChat(receiverId: string): void {
+      if (!this.userId) throw new Meteor.Error('unauthorized',
+        'User must be logged-in to create a new chat');
+
+      check(receiverId, nonEmptyString);
+
+      if (receiverId == this.userId) throw new Meteor.Error('illegal-receiver',
+        'Receiver must be different than the current logged in user');
+
+      const chatExists = !!Chats.collection.find({
+        memberIds: {$all: [this.userId, receiverId]}
+      }).count();
+
+      if (chatExists) throw new Meteor.Error('chat-exists',
+        'Chat already exists');
+
+      const chat = {
+        memberIds: [this.userId, receiverId]
+      };
+
+      Chats.insert(chat);
+    },
     updateProfile(profile: Profile): void {
       if (!this.userId) throw new Meteor.Error('unauthorized',
         'User must be logged-in to create a new chat');