SMART datagrid v.1 > Classes > CalculatedColumn
Callback function which returns the value of calculated column cell.
It takes precedence over valueExpression.
Defaults to null.
    grid.setColumns([{
        name: "colAmount",
        type: "calced",
        valueType: DataLudi.ValueType.NUMBER, // The default value
        valueCallback: function (column, row) {
            return row.getValue('unit_price') * row.getValue('quantity');
        }
    }, 
        ...
    ]);