From 9ee1d92b5273732265698d67c5d8706894151e1e Mon Sep 17 00:00:00 2001
From: Andreas Svensson <andreas@syranide.com>
Date: Mon, 13 Jan 2014 23:09:53 +0100
Subject: [PATCH] Remove unnecessary tests from insertChildAt and inline it
 instead

---
 src/browser/ui/dom/DOMChildrenOperations.js | 22 ++++++++-------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/browser/ui/dom/DOMChildrenOperations.js b/src/browser/ui/dom/DOMChildrenOperations.js
index d2bc513d68..e2e3de2005 100644
--- a/src/browser/ui/dom/DOMChildrenOperations.js
+++ b/src/browser/ui/dom/DOMChildrenOperations.js
@@ -42,20 +42,14 @@ var textContentAccessor = getTextContentAccessor();
  * @internal
  */
 function insertChildAt(parentNode, childNode, index) {
-  var childNodes = parentNode.childNodes;
-  if (childNodes[index] === childNode) {
-    return;
-  }
-  // If `childNode` is already a child of `parentNode`, remove it so that
-  // computing `childNodes[index]` takes into account the removal.
-  if (childNode.parentNode === parentNode) {
-    parentNode.removeChild(childNode);
-  }
-  if (index >= childNodes.length) {
-    parentNode.appendChild(childNode);
-  } else {
-    parentNode.insertBefore(childNode, childNodes[index]);
-  }
+  // By exploiting arrays returning `undefined` for an undefined index, we can
+  // rely exclusively on `insertBefore(node, null)` instead of also using
+  // `appendChild(node)`. However, using `undefined` is not allowed by all
+  // browsers so we must replace it with `null`.
+  parentNode.insertBefore(
+    childNode,
+    parentNode.childNodes[index] || null
+  );
 }
 
 var updateTextContent;