title: Multi grouping in extjs 5
body: <p>One way of doing the multi column grouping is to override the Grouper function to provide the necessary functionality..</p>
  
  <pre><code>Ext.util.Grouper.override({
  
      getGroupString: function (item) {
          return item.get('account') + ', Currency: ' + item.get('currCd');
      }
  
  });
  
  // Define summary store
  Ext.define('xxx.store.Summaries', {
      extend: 'Ext.data.JsonStore',
      alias: 'store.summaries',
      requires: ['xxx.view.summary.SummaryGrouper'],
      model: 'xxx.model.Summary',
      storeId: 'summaryStore',
  
      grouper: {
          property: 'account'
      },
  </code></pre>
  
  <p>The other way of doing this grouping is by grouper property in store.</p>
  
  <pre><code>    grouper: {
          property: 'account',
           groupFn: function (item) {
               return item.get('account') + ', Currency: ' + item.get('currCd');
           }
      },
  </code></pre>
  
  <p><em>This one works the first time, but, when I refresh, it doesn't take the groupFn that I give it just groups by account. I am guessing this has something to do with the configuration.</em> Could you suggest why?</p>
  
  <p>Another way of doing this is by extending Grouper, but, I think I am doing something wrong. this is not getting called or maybe I am doing something wrong.</p>
  
  <p>// Define summary grouper</p>
  
  <pre><code>Ext.define('Banking.view.summary.SummaryGrouper', {
      extend: 'Ext.util.Grouper',
      alias: 'widget.summaryGrouper',
      isGrouper: true,
      initComponent: function () {
          this.callParent(arguments);
      },
      config: {
          groupFn: function(record) {
               return record.get('account') + ', Currency:' + record.get('currCd');
          },
          sortProperty: 'account'
      },
      constructor:function(cfg){
          this.callParent(arguments);//Calling the parent class constructor
          this.initConfig(cfg);//Initializing the component
      }
  });
  </code></pre>
  
  <p>Could you suggest what am I doing wrong here when I am extending the Grouper class?</p>