From b0fe9f059ca310578ac5e26c52861734ff18c454 Mon Sep 17 00:00:00 2001
From: desrosj <desrosj@git.wordpress.org>
Date: Tue, 22 Dec 2020 15:44:08 +0000
Subject: [PATCH] Twenty Twenty-One: Only load IE specific polyfills when
 actually using Internet Exploreer.

The `twenty-twenty-one-ie11-polyfills` script now has a `null` source, and the new `twenty-twenty-one-ie11-polyfills-asset` (which points to the actual `polyfills.js` source) will be loaded only if IE is detected by through the use of `wp_get_script_polyfill()`.

Because the original script name remains the same, this change is backwards compatible with any code registering `twenty-twenty-one-id11-polyfills` as a script dependency.

Props poena, ismail.elkorchi, peterwilsoncc
Fixes #52098.
Built from https://develop.svn.wordpress.org/trunk@49865


git-svn-id: http://core.svn.wordpress.org/trunk@49584 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 .../themes/twentytwentyone/functions.php      | 23 +++++++++++++++++--
 wp-includes/version.php                       |  2 +-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/wp-content/themes/twentytwentyone/functions.php b/wp-content/themes/twentytwentyone/functions.php
index 652fc50db1..1139c3b659 100644
--- a/wp-content/themes/twentytwentyone/functions.php
+++ b/wp-content/themes/twentytwentyone/functions.php
@@ -396,7 +396,7 @@ add_action( 'after_setup_theme', 'twenty_twenty_one_content_width', 0 );
 function twenty_twenty_one_scripts() {
 	// Note, the is_IE global variable is defined by WordPress and is used
 	// to detect if the current browser is internet explorer.
-	global $is_IE;
+	global $is_IE, $wp_scripts;
 	if ( $is_IE ) {
 		// If IE 11 or below, use a flattened stylesheet with static values replacing CSS Variables.
 		wp_enqueue_style( 'twenty-twenty-one-style', get_template_directory_uri() . '/assets/css/ie.css', array(), wp_get_theme()->get( 'Version' ) );
@@ -416,14 +416,33 @@ function twenty_twenty_one_scripts() {
 		wp_enqueue_script( 'comment-reply' );
 	}
 
+	// Register the IE11 polyfill file.
 	wp_register_script(
-		'twenty-twenty-one-ie11-polyfills',
+		'twenty-twenty-one-ie11-polyfills-asset',
 		get_template_directory_uri() . '/assets/js/polyfills.js',
 		array(),
 		wp_get_theme()->get( 'Version' ),
 		true
 	);
 
+	// Register the IE11 polyfill loader.
+	wp_register_script(
+		'twenty-twenty-one-ie11-polyfills',
+		null,
+		array(),
+		wp_get_theme()->get( 'Version' ),
+		true
+	);
+	wp_add_inline_script(
+		'twenty-twenty-one-ie11-polyfills',
+		wp_get_script_polyfill(
+			$wp_scripts,
+			array(
+				'Element.prototype.matches && Element.prototype.closest && window.NodeList && NodeList.prototype.forEach' => 'twenty-twenty-one-ie11-polyfills-asset',
+			)
+		)
+	);
+
 	// Main navigation scripts.
 	if ( has_nav_menu( 'primary' ) ) {
 		wp_enqueue_script(
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a7ff2cce13..58e13eb26f 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-alpha-49864';
+$wp_version = '5.7-alpha-49865';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.