Check Pusher for active channel before unsubscribe to fix uncaught exception. Fix chrismccord#42.

chrismccord · chrismccord · commit c698ebf67355 · 2013-05-29T23:40:10.000-04:00
diff --git a/app/assets/javascripts/sync.coffee.erb b/app/assets/javascripts/sync.coffee.erb
@@ -95,7 +95,8 @@ class Sync.Pusher
 
 
   unsubscribeAll: ->
-    @client.unsubscribe(subscription) for subscription in @subscriptions
+    for subscription in @subscriptions
+      @client.unsubscribe(subscription) if @client.channel(subscription)?
     @subscriptions = []
 
 
