From c0fc6f3ccac3475df01f0aae8cca46dd08b724aa Mon Sep 17 00:00:00 2001
From: junghwan-park <junghwan.park@nhnent.com>
Date: Thu, 9 May 2019 11:28:06 +0900
Subject: [PATCH 1/2] fix: Check HTMLDocument constructor exists first for IE10
 (fixes: fabricjs/fabric.js#5677)

---
 HEADER.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/HEADER.js b/HEADER.js
index 775c6a1e6b9..4c2b3db2910 100644
--- a/HEADER.js
+++ b/HEADER.js
@@ -10,7 +10,9 @@ else if (typeof define === 'function' && define.amd) {
 }
 /* _AMD_END_ */
 if (typeof document !== 'undefined' && typeof window !== 'undefined') {
-  if (document instanceof HTMLDocument) {
+  var DocumentConstructor = typeof HTMLDocument !== 'undefined' ? HTMLDocument : Document;
+
+  if (document instanceof DocumentConstructor) {
     fabric.document = document;
   }
   else {

From 71e400e0d07fc7e369b69350706ed9b299803993 Mon Sep 17 00:00:00 2001
From: junghwan-park <junghwan.park@nhnent.com>
Date: Wed, 29 May 2019 11:53:46 +0900
Subject: [PATCH 2/2] fix: Remove 'var' definition & use ternary operation

---
 HEADER.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/HEADER.js b/HEADER.js
index 4c2b3db2910..0e1cb443edf 100644
--- a/HEADER.js
+++ b/HEADER.js
@@ -10,9 +10,7 @@ else if (typeof define === 'function' && define.amd) {
 }
 /* _AMD_END_ */
 if (typeof document !== 'undefined' && typeof window !== 'undefined') {
-  var DocumentConstructor = typeof HTMLDocument !== 'undefined' ? HTMLDocument : Document;
-
-  if (document instanceof DocumentConstructor) {
+  if (document instanceof (typeof HTMLDocument !== 'undefined' ? HTMLDocument : Document)) {
     fabric.document = document;
   }
   else {