An abstract class used to transform values from one representation to another.
- iOS 3.0+
- macOS 10.3+
- tvOS 9.0+
- watchOS 2.0+
An application creates a subclass of
NSValue, overriding the necessary methods to provide the required custom transformation.
A relatively trivial value transformer takes an object and returns a string based on the object’s class type. This transformer is not reversible because it doesn't make sense to transform a class name into an object. The implementation for such a value transformer could be the following: