From c6f568f99bd2f4e753cb42199d2767722e9934d4 Mon Sep 17 00:00:00 2001
From: drnextgis <rykovd@gmail.com>
Date: Mon, 21 Mar 2016 12:26:14 +0600
Subject: [PATCH] assertion to check that there's a DOM node for target element

---
 src/ol/map.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ol/map.js b/src/ol/map.js
index f3159e73c9..940e85ff9e 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -1064,7 +1064,12 @@ ol.Map.prototype.handleTargetChanged_ = function() {
   // If it's not now an Element we remove the viewport from the DOM.
   // If it's an Element we append the viewport element to it.
 
-  var targetElement = this.getTargetElement();
+  var targetElement;
+  if (this.getTarget()) {
+    targetElement = this.getTargetElement();
+    goog.asserts.assert(targetElement !== null,
+        'expects a non-null value for targetElement');
+  }
 
   if (this.keyHandlerKeys_) {
     for (var i = 0, ii = this.keyHandlerKeys_.length; i < ii; ++i) {