From 32ffd9d804e92b18898312581b9d4af61e59512a Mon Sep 17 00:00:00 2001
From: Vaadin Bot <vaadin-bot@users.noreply.github.com>
Date: Thu, 12 May 2022 15:21:29 +0200
Subject: [PATCH] fix: do not throw on Tab if grid has tabindex (#3838) (#3839)

Co-authored-by: Serhii Kulykov <iamkulykov@gmail.com>
---
 .../grid/src/vaadin-grid-keyboard-navigation-mixin.js  |  5 +++++
 packages/grid/test/keyboard-navigation.test.js         | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/packages/grid/src/vaadin-grid-keyboard-navigation-mixin.js b/packages/grid/src/vaadin-grid-keyboard-navigation-mixin.js
index 2318e57fcaa..184e15d6b05 100644
--- a/packages/grid/src/vaadin-grid-keyboard-navigation-mixin.js
+++ b/packages/grid/src/vaadin-grid-keyboard-navigation-mixin.js
@@ -617,6 +617,11 @@ export const KeyboardNavigationMixin = (superClass) =>
     _onTabKeyDown(e) {
       const focusTarget = this._predictFocusStepTarget(e.composedPath()[0], e.shiftKey ? -1 : 1);
 
+      // Can be undefined if grid has tabindex
+      if (!focusTarget) {
+        return;
+      }
+
       // Prevent focus-trap logic from intercepting the event.
       e.stopPropagation();
 
diff --git a/packages/grid/test/keyboard-navigation.test.js b/packages/grid/test/keyboard-navigation.test.js
index b20e8531a15..de98e4ca827 100644
--- a/packages/grid/test/keyboard-navigation.test.js
+++ b/packages/grid/test/keyboard-navigation.test.js
@@ -2183,6 +2183,16 @@ describe('empty grid', () => {
     // Expect programmatic focus on focus exit element
     expect(grid.shadowRoot.activeElement).to.equal(grid.$.focusexit);
   });
+
+  it('should not throw on Shift + Tab when grid has tabindex', () => {
+    grid.setAttribute('tabindex', '0');
+
+    grid.focus();
+
+    expect(() => {
+      shiftTab(grid);
+    }).to.not.throw(Error);
+  });
 });
 
 describe('hierarchical data', () => {