title: react map es6 arrow function doesn't work
body: <p>I have below code and it render nothing, I wonder where is my mistake, I did not see any error in the console.</p>
  
  <pre><code>var App = React.createClass({
     getInitialState(){
     return {
       items:[1,2,3]
     }
     },
     renderItem(){
     this.state.items.map((item,i)=&gt; &lt;li key={i}&gt;{item}&lt;/li&gt;)
     },
     render(){
        return(
        &lt;ul&gt;
          {this.renderItem}
        &lt;/ul&gt;
        )
     }
  })
  
  React.render(&lt;App /&gt;, document.getElementById('container'));
  </code></pre>
  
  <p><a href="http://jsfiddle.net/3Ley7uac/" rel="nofollow">http://jsfiddle.net/3Ley7uac/</a></p>
  
  <p>Need advise.</p>