you did not change the validate function, by change the isValid function because javascript is a pass by ref language and you change the pointer of isValid var and not the pointer in the validate function it self, it still point to the old function :) ... for a lot of people the "pass by ref" and pointers is confuse .. so i want to "point" this out :) ps. this can be a good idea for a video, you are good to explain

R.ifElse(isValid, R.identity, R.F) the R.F and R.T is for cases where you do not care about the parameters and only want to return false or true, if you get a long chain of functions in a pipe/compose