programmatically change selected rows in a slickgrid

Using slickgrid, I need to select/deselect rows on the fly, and here is my code, it seems to work but sounds a bit suboptimal really, is there any smater means to do this ?

// turn records checkbox on or off depending on 'checked'

function set_checkbox (record, checked) {  
   var id = record[primary_key];
   var index = dataview.getIdxById(id);
   var selectedRows=this.slick_grid.getSelectedRows();
   if (checked) // add index in current list
      selectedRows=selectedRows.concat(index);
   else // remove index from current list
      selectedRows=selectedRows.filter(function(idx) {return idx!=index;});
   this.slick_grid.setSelectedRows(selectedRows);
}   

The grid is initialized with this selection model here:

grid.setSelectionModel (new Slick.RowSelectionModel ({selectActiveRow: false}));