map is:exact -package:text -package:bytestring -package:aeson -package:case-insensitive -package:Cabal-syntax -package:base-compat-batteries -package:containers -package:amazonka-core -package:filepath -package:os-string -package:dense-linear-algebra package:pipes

Apply a function to all values flowing downstream
map id = cat

map (g . f) = map f >-> map g