title: mobx - Leading decorators must be attached to a class declaration
body: <p>I want to use the MobX decorators, but when I try to run my code, I get the following error message:</p>
  
  <pre><code>Leading decorators must be attached to a class declaration
  </code></pre>
  
  <p>My application is storing data in Datastores from nedb and I want to observe them with mobx.</p>
  
  <p>So for example, if I have the following code:</p>
  
  <pre><code>import { observable } from 'mobx';
  import Datastore from 'nedb';
  
  @observable projectsDb = new Datastore({
      filename: __dirname + './projects.json',
      autoload: true,
      timestampData: true,
  });
  
  export default projectsDb;
  </code></pre>
  
  <p>When I start my Electron App I use the following command:</p>
  
  <pre><code>"browserify -t [ babelify --presets [ react es2015 stage-1] --plugins [transform-decorators-legacy] ] app/app.jsx -o app/js/app.js &amp;&amp; stylus app/css/styles.styl -o app/css/styles.css &amp;&amp; electron app/main.js",
  </code></pre>
  
  <p>Also all devDepenendencies and Dependencies are added to my package.json. </p>
  
  <p>Is there any error in my "start"-command or any misunderstanding in the concept of observable here?</p>