ramba.js

data = compose(
    over(lensPath(["keys"]), append(NEW_ITEM_ID)),
    over(lensPath(["count"]), x => x + 1),
    set(lensPath(["items", NEW_ITEM_ID]), {
      id: NEW_ITEM_ID,
      name: "ITEM-NEW",
      value: 0
    })
)(INITIAL_DATA);