how to sortOn cell color on ExcelScript for web?

[Wolfeius]

I am trying to sort in descending order the cells with a 'rose' background, as you can do in the 'filter' or 'custom sort' but with ExcelScript for web:

 range.getSort().apply([ {
    ascending: false,
    key: 5,
    sortOn: ExcelScript.SortOn.cellColor,
    subField: "rose"
 }]);

But it does not sort. I am pretty sure I am misusing the subField field, but the microsoft docs are not very helpful. If I just sort in ascending or descending order, it works:

 range.getSort().apply([ {
    ascending: true,
    key: 5
 }]);

How can I use properly the sortOn feature to sort by cellColor, or other property?

I have tried to record a macro but it does not have the sortOn or subField fields:

selectedSheet.getRange("A8:K50").getSort().apply([{key: 0, ascending: true}], false, true);