title: async / await not working in combination with fetch
body: <p>I'm trying to use ES7 <code>async</code> / <code>await</code> together with <code>fetch</code>. I know I'm close but I can't get it to work. Here is the code:</p>
  
  <pre><code>class Bar {
      async load() {
          let url =  'https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
          try {
              response = await fetch(url);
              return response.responseText;
          } catch (e) {
              return e.message;
          }
      }
  }
  </code></pre>
  
  <p>which I use as follows:</p>
  
  <pre><code>let bar = new Bar();
  bar.load().then(function (val) {
      console.log(val);
  });
  </code></pre>
  
  <p><a href="http://codepen.io/anon/pen/XmNBEJ" rel="noreferrer">DEMO</a></p>
  
  <p>For some reason I always get into the <code>catch</code> with the message</p>
  
  <pre><code>response is not defined
  </code></pre>
  
  <p>Any suggestions what I do wrong ?</p>
  
  <p>UPDATE: As suggested in the comments, it might be an issue with <code>fetch</code>, so I tried a simplified (ES5) version:</p>
  
  <pre><code>&lt;!doctype html&gt;
  
  &lt;html&gt;
      &lt;head&gt;      
          &lt;script&gt;
              var url =  'https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
              fetch(url, {method: 'get', mode: 'cors'}).then(function (response) {
                         console.log(response.responseText);
                 });
          &lt;/script&gt;
      &lt;head&gt;
  
     &lt;body&gt;&lt;/body&gt;
  &lt;html&gt;
  </code></pre>
  
  <p>And still doesn't work :( However, if I replace fetch it works:</p>
  
  <pre><code>var request = new XMLHttpRequest();
  request.open("GET", url, false);
  request.send(null);
  console.log(request.responseText);
  </code></pre>