Guide applies to: modern
Ext.grid.cell.Cell is the default cell type, and the most useful.
Gridcell simply renders the string value for the dataIndex value.
formatter
You may specify a formatter that converts the dateIndex using an Ext.util.Format method, or a method you provide.
tpl
You may also specify a tpl, which uses an Ext.XTemplate that can reference any record field.
renderer
And finally, you may provide a +renderer+ function to provide the rendered value.