Ticket #42495: 42495.1.diff

src/wp-includes/js/customize-selective-refresh.js

@@ -488 +488 @@
                                 wp.mediaelement.initialize();
                         }
 
+                        if ( wp.playlist ) {
+                                wp.playlist.initialize();
+                        }
+
                         /**
                          * Announce when a partial's placement has been rendered so that dynamic elements can be re-built.
                          */

src/wp-includes/js/mediaelement/wp-playlist.js

@@ -3 +3 @@
 (function ($, _, Backbone) {
         'use strict';
 
+        window.wp = window.wp || {};
+
         var WPPlaylistView = Backbone.View.extend(/** @lends WPPlaylistView.prototype */{
                 /**
                  * @constructs
@@ -168 +170 @@
                 }
         });
 
-    $(document).ready(function () {
-                $('.wp-playlist').each( function() {
-                        return new WPPlaylistView({ el: this });
+        function initialize() {
+                // Only initialize new playlists
+                $( '.wp-playlist:not(:has(.mejs-container))' ).each( function() {
+                        new WPPlaylistView( { el: this } );
                 } );
-    });
+        }
+
+        window.wp.playlist = {
+                initialize: initialize
+        };
+
+        $(document).ready( initialize );
 
         window.WPPlaylistView = WPPlaylistView;
 

src/wp-includes/widgets/class-wp-widget-text.php

@@ -57 +57 @@
 
                 wp_add_inline_script( 'text-widgets', sprintf( 'wp.textWidgets.idBases.push( %s );', wp_json_encode( $this->id_base ) ) );
 
+                if ( $this->is_preview() ) {
+                        add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_preview_scripts' ) );
+                }
+
                 // Note that the widgets component in the customizer will also do the 'admin_print_scripts-widgets.php' action in WP_Customize_Widgets::print_scripts().
                 add_action( 'admin_print_scripts-widgets.php', array( $this, 'enqueue_admin_scripts' ) );
 
@@ -393 +397 @@
                 return $instance;
         }
 
+        /**
+         * Enqueue preview scripts.
+         *
+         * These scripts normally are enqueued just-in-time when a playlist shortcode is used.
+         * However, in the customizer, a playlist shortcode may be used in a text widget and
+         * dynamically added via selective refresh, so it is important to unconditionally enqueue them.
+         *
+         * @since 4.9.2
+         */
+        public function enqueue_preview_scripts() {
+                require_once( dirname( dirname( __FILE__ ) ) . '/media.php' );
+
+                wp_playlist_scripts( 'audio' );
+                wp_playlist_scripts( 'video' );
+        }
+
         /**
          * Loads the required scripts and styles for the widget control.
          *