title: Add a property to an object returned by a function?
body: <p>I would like to know if there is a way to get all properties of 'myFields' assigned in a single statement ?</p>
  
  <p>This works:</p>
  
  <pre><code>function fieldMap(namesString) {
      var result = {};
      var names = namesString.split(' ');
      for (index in names) {
          var name = names[index];
          result[name] = name + '/text()';
      }
      return result;
  }
  var myFields = fieldMap('title rating author url');
  myFields['cover']="@cover";
  </code></pre>
  
  <p>This doesn't work:</p>
  
  <pre><code>var myFields = fieldMap('title rating author url')['cover']='@cover';
  </code></pre>