Replace var with let and rename mongoose.js to ChatData.js

mongoose.js → ChatData.js

@@ -14,10 +14,10 @@ class ChatData {
   }
 
   addChat (senderId, receiverId, content) {
-    var participantIds = [ senderId, receiverId ]
+    let participantIds = [ senderId, receiverId ]
     participantIds.sort()
 
-    var chat = {
+    let chat = {
       owner_id: senderId,
       content: content
     }
@@ -30,7 +30,7 @@ class ChatData {
         }
 
         if (!done) {
-          var chat = new this.ChatModel({
+          let chat = new this.ChatModel({
             participant_ids: participantIds,
             chats: [{
               owner_id: senderId,
@@ -44,7 +44,7 @@ class ChatData {
   }
 
   findChat (firstParticipantId, secondParticipantId) {
-    var participantIds = [ firstParticipantId, secondParticipantId ]
+    let participantIds = [ firstParticipantId, secondParticipantId ]
     participantIds.sort()
 
     this.ChatModel.findOne({ participant_ids: participantIds }, function (err, result) {
@@ -53,7 +53,7 @@ class ChatData {
       }
 
       if (result) {
-        var chats = result.chats
+        let chats = result.chats
 
         chats.forEach(function (chat) {
           console.log(chat)