Actioncolumn getClass params

HTML

<link rel="stylesheet" href="http://cdn.sencha.io/ext-4.2.0-gpl/resources/css/ext-all.css">
<script src="http://cdn.sencha.io/ext-4.2.0-gpl/ext-all.js"></script>

JavaScript

Ext.create('Ext.data.Store', {
    storeId:'employeeStore',
    fields:['lastname', 'action_val'],
    data:[
        {lastname:"Scott", action_val: 'some val'},
        {lastname:"Schrute", action_val: 'some val2'}
    ]
});

Ext.create('Ext.grid.Panel', {
    title: 'Action Column Demo',
    store: Ext.data.StoreManager.lookup('employeeStore'),
    columns: [
        {text: 'Last Name',  dataIndex:'lastname'},
        {
            xtype:'actioncolumn',
            width:50,
            dataIndex:'action_val',
            items: [{
                icon: 'http://cdn.sencha.io/ext-4.2.0-gpl/examples/shared/icons/fam/cog_edit.png',
                getClass: function(v) {
                    console.log('The value is:', v);
                    alert(v);
                }
            }]
        }
    ],
    width: 250,
    renderTo: Ext.getBody()
});