From 1eaef0bf479fcb3fe17b77187e8cab35252d5d8a Mon Sep 17 00:00:00 2001
From: Bingqing Wang <bingtsingw@gmail.com>
Date: Thu, 24 Sep 2020 13:03:31 +0800
Subject: [PATCH] fix: check if document is truthy before create node

---
 packages/core-js/internals/microtask.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/core-js/internals/microtask.js b/packages/core-js/internals/microtask.js
index 6df180c61def..36804bed9771 100644
--- a/packages/core-js/internals/microtask.js
+++ b/packages/core-js/internals/microtask.js
@@ -39,7 +39,7 @@ if (!queueMicrotask) {
       process.nextTick(flush);
     };
   // browsers with MutationObserver, except iOS - https://github.com/zloirock/core-js/issues/339
-  } else if (MutationObserver && !IS_IOS) {
+  } else if (MutationObserver && !IS_IOS && document) {
     toggle = true;
     node = document.createTextNode('');
     new MutationObserver(flush).observe(node, { characterData: true });