Hello guys! I'm writing export feature for my pivot table and have some issue. When exporting without column filled i'm having error fired by \koolreport\excel\PivotTableBuilder class in method dataStoreToSpreadsheet in line:

$value = $mappedColFields[$f];

When i haven't columns (only total column which represented as root) $mappedColFields is empty and thrown error "undefined array key "root"". I'm fixed this by providing null check like:

$value = $mappedColFields[$f] ?? null;

I'm didn't think thats a good idea to change vendor files or rewrite by extending. So may you include this fix in next builds or there some another fixes presents ?