title: Read class decorator information in typescript
body: <p>I have a class decorated with attributes.</p>
  
  <p>I would like to read the attributes in the constructor ( or other method ).</p>
  
  <p>I have tried using Reflect and all possible methods on that class but I only get undefined</p>
  
  <p>The class looks like this</p>
  
  <pre><code>@inject(Element)
  @bindable('color')
  export class Messagebarhost {
  
  public element: HTMLElement;
  
    constructor(element) {
    console.log(Reflect.getMetadata("design:paramtypes", this));
    // prints undefined
    // somehow I want to read the value 'color'
    }
  }
  </code></pre>
  
  <p>If I set a breakpoint in the bundled js file where the decorators are created. Below line will print the correct value if I enter it in the debugger</p>
  
  <pre><code>r.__metadata__.undefined["aurelia:resource"].properties[0]
  </code></pre>