AnyType
Any type (the top type of this type system).
A variable of this type can contain any value, including undefined
and null and any JS value. This type supports a very limited set
of Scala operations, the ones common to all values. Basically only
reference equality tests and instance tests. It also supports all
JavaScript operations, since all Scala objects are also genuine
JavaScript objects.
The type java.lang.Object in the back-end maps to AnyType because it
can hold JS values (not only instances of Scala.js classes).