title: Underscore's _.keys function only returning numermic indexes of keys not the value of keys in an array
body: <p>I am trying to get the value of the key to set autocomplete values for my drop downs. The user will enter "LOAN" in the "#currentSelectedLevel" field and jQuery will populate all of the ".episysFieldName" fields with the keys from the loansFields.</p>
  
  <pre><code>if($("#currentSelectedLevel").val()=="LOAN"){                
      $(".levelFieldName").autocomplete('option', 'source', _.keys(loanFields));}
  
  
  var loanFields = [
  
    {"BALANCE": "MONEY"},
    {"OPENDATE": "DATE"},
    {"CLOSEDATE": "DATE"}
  ];
  </code></pre>
  
  <p>When I do an alert I just get the indexes of the values. [0,1,2]. I need it to return "BALANCE", "OPENDATE", "CLOSEDATE".</p>
  
  <pre><code>alert( _.keys(loanFields));
  </code></pre>
  
  <p>I have the jQuery code working fine when I just use strings in the array.</p>
  
  <p>Note:  The reason I am starting to use objects/key value pairs is because in the future I need to know the type of the field and possibly other properties. I believe my issue is how I am structuring the object within the array. Any help would be greatly appreciated.  </p>