Fix use of private function from macro

This ends up expanding in the caller's namespace, which references the
private `wrap-fx` and leads to a compiler warning under Figwheel.  I
believe Shadow is suppressing these so it wasn't caught.

Author: SevereOverfl0w

src/helix/hooks.cljc

@@ -13,6 +13,7 @@
                   local vars.  Not available for the function form of a hook."
   #?(:clj (:require [helix.impl.analyzer :as hana])
      :cljs (:require
+            [helix.impl.hooks :refer [wrap-fx]]
             ["react" :as react]
             [goog.object :as gobj]))
   #?(:cljs (:require-macros [helix.hooks])))
@@ -117,16 +118,6 @@
      "Just react/useContext"
      react/useContext))
 
-
-;; React `useEffect` expects either a function or undefined to be returned
-#?(:cljs
-   (defn- wrap-fx [f]
-     (fn wrap-fx-return []
-       (let [x (f)]
-         (if (fn? x)
-           x
-           js/undefined)))))
-
 #?(:clj
    (defn deps-macro-body [env deps body simple-body-ok? deps->hook-body]
      (cond

src/helix/impl/hooks.cljs

@@ -0,0 +1,9 @@
+(ns helix.impl.hooks)
+
+;; React `useEffect` expects either a function or undefined to be returned
+(defn wrap-fx [f]
+  (fn wrap-fx-return []
+    (let [x (f)]
+      (if (fn? x)
+        x
+        js/undefined))))