Mastering TypeScript - Fourth Edition

6

Decorators

Decorators in TypeScript provide a way of programmatically tapping into the process of defining a class. Remember that a class definition describes the shape of a class, what properties it has, and what methods it defines. When an instance of a class is created, these properties and methods become available on the class instance. Decorators, however, allow us to inject code into the actual definition of a class, before a class instance has been created. They are similar to attributes in C#, or annotations in Java.

JavaScript decorators are currently only at a draft or stage 2 level, meaning that it may take a while before they are adopted into the JavaScript standard. TypeScript, however, has supported decorators for quite some ...