CLJC: address (some of) Daniel's review comments

src/re_frame/interop.clj

@@ -1,7 +1,31 @@
-(ns re-frame.interop)
+(ns re-frame.interop
+  (:import java.util.concurrent.Executors))
+
+
+;; The purpose of this file is to provide JVM-runnable implementations of the
+;; CLJS equivalents in interop.cljs.
+;;
+;; These implementations are to enable you to bring up a re-frame app on the JVM
+;; in order to run tests, or to develop at a JVM REPL instead of a CLJS one.
+;;
+;; Please note, though, that the purpose here *isn't* to fully replicate all of
+;; re-frame's behaviour in a real CLJS environment.  We don't have Reagent or
+;; React on the JVM, and we don't try to mimic the stateful lifecycles that they
+;; embody.
+;;
+;; In particular, if you're performing side effects in any code that's triggered
+;; by a change to a Ratom's value, and not via a call to `dispatch`, then you're
+;; going to have a hard time getting any accurate tests with this code.
+;; However, if your subscriptions and Reagent render functions are pure, and
+;; your side-effects are all managed by event handlers, then hopefully this will
+;; allow you to write some useful tests that can run on the JVM.
+
+
+(defonce ^:private executor (Executors/newSingleThreadExecutor))
 
 (defn next-tick [f]
-  (.start (Thread. f)))
+  (.execute executor f)
+  nil)
 
 (def empty-queue clojure.lang.PersistentQueue/EMPTY)
 
@@ -10,17 +34,14 @@
 (def debug-enabled? true)
 
 (defn ratom [x]
-  (let [result (atom x)]
-    (alter-meta! result assoc ::ratom? true)
-    result))
+  (atom x))
 
-(defn ratom? [maybe-ratom]
-  (and (satisfies? clojure.lang.IAtom maybe-ratom)
-       (::ratom? (meta maybe-ratom))))
+(defn ratom? [x]
+  (satisfies? clojure.lang.IAtom x))
 
 (defn make-reaction
-  "On JVM Clojure, return an atom-like thing which invokes the given function on
-  every deref. That is, `make-reaction` here provides precisely none of the
+  "On JVM Clojure, return a `deref`-able thing which invokes the given function
+  on every `deref`. That is, `make-reaction` here provides precisely none of the
   benefits of `reagent.ratom/make-reaction` (which only invokes its function if
   the reactions that the function derefs have changed value). But so long as `f`
   only depends on other reactions (which also behave themselves), the only

src/re_frame/interop.cljs

@@ -14,8 +14,8 @@
 (defn ratom [x]
   (reagent.core/atom x))
 
-(defn ratom? [maybe-ratom]
-  (satisfies? reagent.ratom/IReactiveAtom maybe-ratom))
+(defn ratom? [x]
+  (satisfies? reagent.ratom/IReactiveAtom x))
 
 (defn make-reaction [f]
   (reagent.ratom/make-reaction f))

src/re_frame/router.cljc

@@ -227,7 +227,7 @@
         stack  #?(:cljs (->> (js/Error. (str "Event " (first event-v) " dispatched from here:"))
                              .-stack
                              clojure.string/split-lines
-                             (remove #(re-find #"react.inc.js|\(native\)" %))
+                             (remove #(re-find #"react\.inc\.js|\(native\)" %))
                              (clojure.string/join "\n"))
                   :clj  "n/a")]
     (if (nil? event-v)