diff --git a/src/browser/datomish/cljify.cljs b/src/browser/datomish/cljify.cljs
new file mode 100644
index 00000000..7c02f5bb
--- /dev/null
+++ b/src/browser/datomish/cljify.cljs
@@ -0,0 +1,47 @@
+(ns datomish.cljify)
+
+(defn cljify
+  "Does what `(js->clj o :keywordize-keys true) is supposed to do, but works
+  in environments with more than one context (e.g., web browsers).
+
+  See <http://dev.clojure.org/jira/browse/CLJS-439?focusedCommentId=43909>.
+
+  Note that Date instances are passed through."
+  [o]
+  (cond
+    (nil? o)
+    nil
+
+    ;; Primitives.
+    (or
+      (true? o)
+      (false? o)
+      (number? o)
+      (string? o)
+      ;; Dates are passed through.
+      (not (nil? (aget (aget o "__proto__") "getUTCMilliseconds"))))
+    o
+
+    ;; Array.
+    (.isArray js/Array o)
+    (let [n (.-length o)]
+      (loop [i 0
+             acc (transient [])]
+        (if (< i n)
+          (recur (inc i) (conj! acc (cljify (aget o i))))
+          (persistent! acc))))
+
+    ;; Object.
+    (not (nil? (aget (aget o "__proto__") "hasOwnProperty")))
+    (let [a (.keys js/Object o)
+          n (.-length a)]
+      (loop [i 0
+             acc (transient {})]
+        (if (< i n)
+          (let [key (aget a i)]
+            (recur (inc i) (assoc! acc
+                                   (keyword key)
+                                   (cljify (aget o key)))))
+          (persistent! acc))))
+
+    :else o))
diff --git a/src/node/datomish/cljify.cljs b/src/node/datomish/cljify.cljs
new file mode 100644
index 00000000..3ef64a3f
--- /dev/null
+++ b/src/node/datomish/cljify.cljs
@@ -0,0 +1,7 @@
+(ns datomish.cljify)
+
+(defn cljify
+  "In node, equivalent to `(js->clj o :keywordize-keys true).
+  See <http://dev.clojure.org/jira/browse/CLJS-439?focusedCommentId=43909>."
+  [o]
+  (js->clj o :keywordize-keys true))