From ce3209a439c552eade04cbeba98fe108f2a661d7 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Wed, 29 Jan 2014 20:54:09 +0100
Subject: [PATCH] Improve type checking in ol.Object#bindTo

---
 src/ol/object.js | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/ol/object.js b/src/ol/object.js
index c8eacc40fb..0d643536cf 100644
--- a/src/ol/object.js
+++ b/src/ol/object.js
@@ -235,9 +235,13 @@ ol.Object.prototype.bindTo = function(key, target, opt_targetKey) {
 
   // listen for change:targetkey events
   var eventType = ol.Object.getChangeEventType(targetKey);
-  this.listeners_[key] = goog.events.listen(target, eventType, function() {
-    this.notifyInternal_(key);
-  }, undefined, this);
+  this.listeners_[key] = goog.events.listen(target, eventType,
+      /**
+       * @this {ol.Object}
+       */
+      function() {
+        this.notifyInternal_(key);
+      }, undefined, this);
 
   // listen for beforechange events and relay if key matches
   this.beforeChangeListeners_[key] = goog.events.listen(target,