Mastering TypeScript 3 - Third Edition

Property decorators

Property decorators are decorator functions that can be used on class properties. A property decorator is called with two parameters—the class prototype itself, and the property name. As an example of this, consider the following code:

function propertyDec(target: any, propertyKey : string) { 
    console.log(`target : ${target}`); 
    console.log(`target.constructor : ${target.constructor}`); 
    console.log(`class name : `  
            + `${target.constructor.name}`);   
    console.log(`propertyKey : ${propertyKey}`); 
} 
 
class ClassWithPropertyDec { 
    @propertyDec 
    name: string; 
}

Here, we have defined a property decorator named propertyDec that accepts two parameters—target and propertyKey. The target parameter is of type any, and the propertyKey parameter ...