The issue with function composition in javascript, for me, is that it's difficult to reason that the functions you are composing in fact do have all their types

The issue with function composition in javascript, for me, is that it's difficult to reason that the functions you are composing in fact do have all their types "lining up". I think there was some outfit "loop/recur" that was doing heavily composition-style javascript. They often write the types for function in comments in haskell notation above the actual function definitions.