From d749945ecf9943fad571c594fb9e73c42ebd9bcb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=96=87=E7=BF=BC?= <wenzhixin2010@gmail.com>
Date: Wed, 13 Nov 2019 11:18:46 +0800
Subject: [PATCH] Fixed flat not polyfilled error in vue cli3 (#4694)

---
 CHANGELOG.md       | 1 +
 src/utils/index.js | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8dd8b1f5b1..d40e5bc1de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ ChangeLog
 - **Update:** Fixed `virtualScroll` option bug with treegrid extension.
 - **Update:** Fixed input keyboard bug for mobile extension.
 - **Update:** Fixed detail view column reorder bug for reorder-columns extension.
+- **Update:** Fixed `flat` not polyfilled error in vue cli3.
 - **Update:** Removed `resetWidth` method and use `resetView` instead.
 
 ### 1.15.5
diff --git a/src/utils/index.js b/src/utils/index.js
index ba11ef0198..10d6eea897 100644
--- a/src/utils/index.js
+++ b/src/utils/index.js
@@ -77,7 +77,7 @@ export default {
   },
 
   updateFieldGroup (columns) {
-    const allColumns = columns.flat()
+    const allColumns = [].concat(...columns)
 
     for (const c of columns) {
       for (const r of c) {