map -package:containers -package:charset is:exact -package:insert-ordered-containers -package:invertible -package:bytestring -package:filepath -package:blaze-html package:case-insensitive

map :: FoldCase s2 => (s1 -> s2) -> CI s1 -> CI s2
case-insensitive Data.CaseInsensitive
Transform the original string-like value but keep it case insensitive.