The DataGrid includes the following API you can use to filter data:
getCombinedFilter() / getCombinedFilter(returnDataField)
Gets the total filter that includes filters from the UI elements and the filter applied to the dataSource. If you specify the
returnDataField parameter, the returned value contains data field names instead of getters.
In this demo, you can use the SelectBox widget to filter the grid's dataSource. The "All" item calls the clearFilter() method and the other items call the filter(filterExpr) method.