Updating an Object is creating new element

Question

Iam having an object json

 json :
      {
       Payload:
               {
                 DevInfo:
                        {
                          Bearer: 5
                        }
               }
       }

I updated the value json.Payload.DevInfo.Bearer =6 After updating the value the json structure coming is

   json :
      {
       Payload:
               {
                 DevInfo:
                        {
                          Bearer: 5
                        }
               }
         Payload.DevInfo.Bearer =6
       }
 

Instead of updating the value, new one is getting created I tried Object.assign() by creating new object, still it is not updating