title: Arrow function is considered unexpected token in React component using babel
body: <p>I have this function in one of my react components. </p>
  
  <pre><code>export default class EventTags extends React.Component{
        showAll () =&gt; {
          this.setState({
            showAll: true,
            showBtn: false
          });
        }
  }
  </code></pre>
  
  <p>When webpack watch hits it I get an unexpected token error on the arrow function. I have the transform-es2015-arrow-functions plugin enabled but it doesn't seem to change the outcome. </p>
  
  <p>Any ideas on what i'm doing wrong here?</p>