From ce1486a7cd4b52b9763885f33de60daeeabbdb94 Mon Sep 17 00:00:00 2001
From: Dan Holmsand <holmsand@gmail.com>
Date: Mon, 14 Sep 2015 21:11:33 +0200
Subject: [PATCH] Make sure on-set is valid before allowing change of Reaction

---
 src/reagent/ratom.cljs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/reagent/ratom.cljs b/src/reagent/ratom.cljs
index 7a2a5bc..49c7206 100644
--- a/src/reagent/ratom.cljs
+++ b/src/reagent/ratom.cljs
@@ -285,10 +285,10 @@
 
   IReset
   (-reset! [a newval]
+    (assert (ifn? on-set) "Reaction is read only.")
     (let [oldval state]
       (set! state newval)
-      (when (some? on-set)
-        (on-set oldval newval))
+      (on-set oldval newval)
       (-notify-watches a oldval newval)
       newval))