Initialize a filter with JSFL?

i'm trying to apply a filter to a layer using JSFL, but i only understand how to derive an existing filter from somewhere else. i don't quite know how to initialize/instantiate a filter out of thin air.  Is it possible?

Right now, i'm manually applying a filter to the bottommost layer, and then my JSFL script uses getFiltersAtFrame/setFiltersAtFrame to apply that filter to other layers. i'd love to be able to skip that first manual step, though. 

All of the examples i see in the documentation begin with some form of "getFilters" before using some form of "setFilters." But i don't see any sort of "whatever = new Filter()" intialization, or any way to work with a filter that doesn't preexist.

- Ryan