Using row number as an index, or creating expression column with row number

[sv2]

Is there a way to use row number as an index in the table ?
I am looking for a way to update specific row in an arbitrary dataset, where index column may or may not exist.
To do so, I am adding a column with the row number - by exporting data via view.to_json(), then adding column with the row number to json, and then loading resulting json into the new table.
Looking for a more efficient way to do this ...
One idea how to slightly optimize this - configure expression column with row number in the view, and then export to json and import to table, thus avoiding json manipulation. But I am not sure how to configure such expression column using ExprTk
Would appreciate any help and suggestions !

[texodus]

Internally perspective creates this column already. We should expose this column as a normal perspective column, but don't currently, so there's no way today to do this entirely in-engine today.

You can currently access the internal index column in un-grouped View's only, by providing the id flag when calling a to_*() method, where you'll find the row's internal id in the __ID__ field:

const json = view.to_json({id: true})
const first_row_id = json[0].__ID__;

You can't yet update on it though, e.g. table.update({__ID__: [12], ...}) won't work today, so you'll still need to mutate the data for now.

We're also adding id() as an exprtk function, but this is more of a hack for your use case wrt the former.

[sv2]

Many thanks !