Optimize orderBy when ordering is desc

[hgrubst]

Currently orderBy in thinky optimizes the query if an index is found on the Model.
As described in the documenation :

The command orderBy is optimized only when a string is passed as the first argument.

Unfortunately if you need to orderBy desc, this does not work as you need to pass your query in the form :
User.orderBy(r.desc('lastName')) which is then not passing a string anymore.

Is there a workaround for this ? Or would it be possible to have thinky overload the orderBy method say by adding a 2nd parameter (boolean) as the order of the sort ?

[jojo-tutor]

Same issue here