If you put the function source into edn and the function doesn't depend on anything but core constructs, it would be nearly trivial to eval using the new cljs.js.

If those functions need to call into other ClojureScript namespaces that you've already compiled into your code then the analysis cache would need to be populated so that eval can operate properly.

For reference, here is cljs.js/eval: https://github.com/clojure/clojurescript/blob/v1.7/src/main/...