13.4 Summary
Introduced with Swift 5.1, property wrappers allow the behavior that would normally be placed in the getters and setters of a property implementation to be extracted and reused through the codebase of an app project avoiding the duplication of code within the class and structure declarations. Property wrappers are declared in the form of structures using the @propertyWrapper directive.
Property wrappers are a powerful Swift feature and allow you to add your own custom behavior to the Swift language. In addition to creating your own property wrappers, you will also encounter them when working with the iOS SDK. In fact, pre-defined property wrappers are used extensively when working with SwiftUI as will be covered in later chapters.
