title: Returning max value in a DC.js / Crossfilter group
body: <p>I am wondering how to return the max value from a dc.js group.</p>
  
  <p>For example:</p>
  
  <pre><code>  var dateDim = data.dimension(function(d) {return d.page_id;});
    var hits = dateDim.group().reduceSum(function(d) {return d.commodity_id;}); 
  </code></pre>
  
  <p>This will return a bar chart plotting page_ids on the X axis, against commodity_ids on the Y axis.</p>
  
  <p>However, I would like it to return the amount of commodity_ids on that particular page on the Y axis.</p>
  
  <p>Would it be accomplished with something similar to the max and min dimension functionality?</p>
  
  <pre><code> var minDate = dateDim.bottom(1)[0].page_id;
   var maxDate = dateDim.top(1)[0].page_id;
  </code></pre>
  
  <p>Apologies if the description is unclear.</p>
  
  <p>Thanks</p>