ItemList
@Js
const mixin ItemList : ItemCollection
ItemList is a simple flat list of items
Construct with list of objects that are coercd via Item.make
Empty list
Return if this list contains the given item by reference equality
abstract Bool contains(Item item)
Return if this list contains the given item by reference equality
const static ItemList : empty
Empty list
static new makeList(Obj[] items, Item? self := null)
Construct with list of objects that are coercd via Item.make