How can functionality be added to an existing type?

You can add functionality to an existing type using the following approaches:

• Extension Functions: Allow adding new functions to existing classes without the need for inheritance or modifying the original code.

  // Extension for Int, adding the isEven function
  fun Int.isEven(): Boolean {
      return this % 2 == 0
  }
  

• Decorator Pattern: Creates a new class that wraps an existing object and adds new functionality while preserving the original interface.

• Composite Pattern and Strategy Pattern: Can be used for more complex cases where functionality depends on state or is chosen dynamically.

• Adapter Pattern: Allows using an existing class with an interface different from the required one.

• Proxy Pattern: Provides a substitute or intermediary for another object to control access to it or add additional functionality.