It's a data structure so you could do it a number of ways. One idea is to mark routes with metadata and clojure.walk/postwalk it, replacing any routes you want ignored with 'false'

Actually, I have a solution...

[[(if debugging? ["devcards.html" (fn [req] ...)] [])]] works

So [] is like a skip

Another way is

`[[~@(if debugging? [["devcards.html" (fn [req] ...)]] [])]]