title: linq.js group by, aggregate multiple fields
body: <p>I am trying to group my data by 2 properties, and sum two other properties for each group. My code is off just a bit, because I am getting the same sum for both the fields (value and quantity). What am I missing? Thanks!</p>
  
  <p>The code - </p>
  
  <pre><code>var linq = Enumerable.from(data);
          var result = linq
              .groupBy(
                  "{ pCo: $.portCo , sName: $.secName }",
                  "$.value, $.quantity",
                  "{ portCo: $.pCo, security: $.sName, value: $$.sum($.value), quantity: $$.sum($.quantity) }",
                  "$.pCo + ' ' + $.secName")
              .toArray();
  </code></pre>