How can I name fields when I create a new table using map?

InfluxDB 2
1

I have several pivotized tables grouped by a tag. I multiply valueA with valueB to create a new variable r.valueC. Is it possible to create the fieldname of “valueC” a string in this context?

I refer to map() function | Flux Documentation
[…]
|> pivot(columnKey: [“_field”], rowKey: [“_time”], valueColumn: “_value”)
|> map(
fn: (r) => ({Time: r.time, valueC: r.valueA* r.valueB}),
// i want: "valueC{r.tagA}": r.valueA * r.valueB
)