Filtering DataGrid column by range

I'm trying to filter DataGrid by range of values in one column. I added DataGrid, added two textboxes debljinaOd (eng. thicknessFrom) and debljinaDo (eng. thicknessTo). Column in DataGrid that I'm trying to filter is Debljina (eng. Thickness). I added button and defined onClick event and executed this.grid0.callLoadData(). Button reloads DataGrid.

I followed this tutorial:
and created custom filter but if I set DataGrid filter to ${this.filter(event.filter)} it gives me error and if I set filter to ${event.filter} then I don't get any errors but DataGrid reloads but not filters.

Column that I'm trying to filter contains only numbers.

Best regards,

Not sure what may have gone wrong. You can check with your Browser developer tools what HTTP requests are being made. Also look for any JS errors.