this.listPoints: PointCollection
   items: Object
          480: PointObject
          500: PointObject
          700: PointObject
          default: PointObject
I have object listPoints that contains a list items as above. I want to add a new item (e.g. 600) to listPoints and this item contains all data/information of default item, and when changing any information in 600 then information of default is not affected. Please help. 
