From eaea2f3b4543d9fbdc572c8f5f1a11e1fc2d664e Mon Sep 17 00:00:00 2001
From: ryelle <ryelle@git.wordpress.org>
Date: Fri, 4 Jun 2021 17:08:00 +0000
Subject: [PATCH] Twenty Twenty-One: Check for navigation element before using
 it.

This prevents a javascript error in case the primary navigation has been removed, for example in a child theme.

Props sushmak.
Fixes #52773.


Built from https://develop.svn.wordpress.org/trunk@51072


git-svn-id: http://core.svn.wordpress.org/trunk@50681 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 .../twentytwentyone/assets/js/primary-navigation.js    | 10 ++++++++--
 wp-includes/version.php                                |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/wp-content/themes/twentytwentyone/assets/js/primary-navigation.js b/wp-content/themes/twentytwentyone/assets/js/primary-navigation.js
index ec559619a1..af9c6df128 100644
--- a/wp-content/themes/twentytwentyone/assets/js/primary-navigation.js
+++ b/wp-content/themes/twentytwentyone/assets/js/primary-navigation.js
@@ -96,7 +96,13 @@ function twentytwentyoneExpandSubMenu( el ) { // jshint ignore:line
 	 */
 	var navMenu = function( id ) {
 		var wrapper = document.body, // this is the element to which a CSS class is added when a mobile nav menu is open
-			mobileButton = document.getElementById( id + '-mobile-menu' );
+			mobileButton = document.getElementById( id + '-mobile-menu' ),
+			navMenuEl = document.getElementById( 'site-navigation' );
+
+		// If there's no nav menu, none of this is necessary.
+		if ( ! navMenuEl ) {
+			return;
+		}
 
 		if ( mobileButton ) {
 			mobileButton.onclick = function() {
@@ -167,7 +173,7 @@ function twentytwentyoneExpandSubMenu( el ) { // jshint ignore:line
 			}
 		} );
 
-		document.getElementById( 'site-navigation' ).querySelectorAll( '.menu-wrapper > .menu-item-has-children' ).forEach( function( li ) {
+		navMenuEl.querySelectorAll( '.menu-wrapper > .menu-item-has-children' ).forEach( function( li ) {
 			li.addEventListener( 'mouseenter', function() {
 				this.querySelector( '.sub-menu-toggle' ).setAttribute( 'aria-expanded', 'true' );
 				twentytwentyoneSubmenuPosition( li );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 3b2a01ee06..f68cdbf4ac 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-51071';
+$wp_version = '5.8-alpha-51072';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.