The method Painter.setStrokeStyle accepts a parameter with type NPDFStokeStyle. Clearly, this was meant to be NPDFStrokeStyle.
https://corymickelson.github.io/NoPoDoFo/documentation/painter.html
https://github.com/corymickelson/NoPoDoFo/blob/master/index.d.ts#L39
Rename enum type?