Angular 2 Components

Using decorators

Decorators are functions that modify a class, property, method, or method parameter. The following example illustrates how to define and use a simple decorator that adds a static parameter to the class:

// decorator function
function AddMetadata (...args) {
  return function (target){
    target.metadata = [...args];
  }
}

// decorator applied
@AddMetadata({ metadata: 'some values'})
class Model {
}

The three dots syntax (...) is the spread operator, which is a feature of JavaScript 2015 that deconstructs the items of a given array.

Decorators versus annotations

You might have heard the term annotations; they are simply metadata related to Angular 2. Before the Angular team decided to use TypeScript, they introduced us to a new language that ...