From f3f03c87519347ec363da8f7455f1d7560b74550 Mon Sep 17 00:00:00 2001
From: ziyoung <dengzhiyang123@126.com>
Date: Thu, 5 Sep 2019 18:27:47 +0800
Subject: [PATCH] Table: fix header table not display

---
 packages/table/src/layout-observer.js | 4 ++--
 packages/table/src/table-layout.js    | 3 ++-
 packages/table/src/table.vue          | 1 +
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/table/src/layout-observer.js b/packages/table/src/layout-observer.js
index 6e9a1c30bc..605a0f200d 100644
--- a/packages/table/src/layout-observer.js
+++ b/packages/table/src/layout-observer.js
@@ -33,10 +33,10 @@ export default {
   },
 
   methods: {
-    onColumnsChange() {
+    onColumnsChange(layout) {
       const cols = this.$el.querySelectorAll('colgroup > col');
       if (!cols.length) return;
-      const flattenColumns = this.tableLayout.getFlattenColumns();
+      const flattenColumns = layout.getFlattenColumns();
       const columnsMap = {};
       flattenColumns.forEach((column) => {
         columnsMap[column.id] = column;
diff --git a/packages/table/src/table-layout.js b/packages/table/src/table-layout.js
index f8c9121c33..82aa323f5d 100644
--- a/packages/table/src/table-layout.js
+++ b/packages/table/src/table-layout.js
@@ -97,7 +97,7 @@ class TableLayout {
     if (this.showHeader && !headerWrapper) return;
 
     // fix issue (https://github.com/ElemeFE/element/pull/16956)
-    const headerTrElm = headerWrapper.querySelector('.el-table__header tr');
+    const headerTrElm = headerWrapper ? headerWrapper.querySelector('.el-table__header tr') : null;
     const noneHeader = this.headerDisplayNone(headerTrElm);
 
     const headerHeight = this.headerHeight = !this.showHeader ? 0 : headerWrapper.offsetHeight;
@@ -119,6 +119,7 @@ class TableLayout {
   }
 
   headerDisplayNone(elm) {
+    if (!elm) return true;
     let headerChild = elm;
     while (headerChild.tagName !== 'DIV') {
       if (getComputedStyle(headerChild).display === 'none') {
diff --git a/packages/table/src/table.vue b/packages/table/src/table.vue
index c4c69172f9..e0061e6282 100644
--- a/packages/table/src/table.vue
+++ b/packages/table/src/table.vue
@@ -383,6 +383,7 @@
       updateScrollY() {
         const changed = this.layout.updateScrollY();
         if (changed) {
+          this.layout.notifyObservers('scrollable');
           this.layout.updateColumnsWidth();
         }
       },