Mastering TypeScript 3 - Third Edition

Decorator syntax

A decorator is simply a function that is called with a specific set of parameters. These parameters are automatically populated by the JavaScript runtime, and contain information about the class to which the decorator has been applied. The number of parameters and the types of these parameters determine where a decorator can be applied. To illustrate the syntax used for decorators, let's define a simple class decorator, as follows:

function simpleDecorator(constructor : Function) { 
    console.log('simpleDecorator called.'); 
} 

Here, we have defined a function named simpleDecorator that takes a single parameter, named constructor of type Function. This simpleDecorator function logs a message to the console indicating that it ...