Class objects can have their types checked.
The below function shows the object inheritance lineage.
type_czech.typeProtos(window)
// Array(4) [ "Window", "EventTarget", "EventTarget", "object" ]
type_czech.typeProtos(document)
// Array(5) [ "HTMLDocument", "Document", "Node", "EventTarget", "object" ]
This is how to get the final object type.
type_czech.typeFinal(window)
// "Window"
type_czech.typeFinal(document)
// "HTMLDocument"
Finally, you can interogate an object to see if it is an instance of a class.
type_czech.typeIsA(document, 'Node')
// true
type_czech.typeIsA(document, 'object')
// true