From 9c52115bf3a2f20bf560dfe8b7b5d26aa1e8372c Mon Sep 17 00:00:00 2001
From: Stefan Penner <stefan.penner@gmail.com>
Date: Thu, 25 Jun 2015 22:47:51 -0700
Subject: [PATCH] only invoke didChange if a node is still present.

---
 packages/ember-metal/lib/chains.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/ember-metal/lib/chains.js b/packages/ember-metal/lib/chains.js
index 662e7333ad2..9da4e325819 100644
--- a/packages/ember-metal/lib/chains.js
+++ b/packages/ember-metal/lib/chains.js
@@ -354,9 +354,13 @@ ChainNode.prototype = {
 
     // then notify chains...
     var chains = this._chains;
+    var node;
     if (chains) {
       for (var key in chains) {
-        chains[key].didChange(events);
+        node = chains[key];
+        if (node !== undefined) {
+          node.didChange(events);
+        }
       }
     }