Ticket #37478: 37478.0.diff

src/wp-includes/js/customize-preview-widgets.js

@@ -376 +376 @@
                                         sidebarPartial.params.sidebarArgs.after_widget
                                 );
 
+                                // Handle rare case where before_widget and after_widget are empty.
+                                if ( ! widgetContainerElement[0] ) {
+                                        return;
+                                }
+
                                 widgetContainerElement.attr( 'data-customize-partial-id', widgetPartial.id );
                                 widgetContainerElement.attr( 'data-customize-partial-type', 'widget' );
                                 widgetContainerElement.attr( 'data-customize-widget-id', widgetId );
@@ -521 +526 @@
                                 widgetClasses;
 
                         emptyWidget = $( widgetTpl );
-                        widgetSelector = emptyWidget.prop( 'tagName' );
-                        widgetClasses = emptyWidget.prop( 'className' );
-
-                        // Remove class names that incorporate the string formatting placeholders %1$s and %2$s.
-                        widgetClasses = widgetClasses.replace( /\S*%[12]\$s\S*/g, '' );
-                        widgetClasses = widgetClasses.replace( /^\s+|\s+$/g, '' );
+                        widgetSelector = emptyWidget.prop( 'tagName' ) || '';
+                        widgetClasses = emptyWidget.prop( 'className' ) || '';
 
                         // Prevent a rare case when before_widget, before_title, after_title and after_widget is empty.
                         if ( ! widgetClasses ) {
                                 return;
                         }
 
-                        if ( widgetClasses ) {
-                                widgetSelector += '.' + widgetClasses.split( /\s+/ ).join( '.' );
-                        }
+                        // Remove class names that incorporate the string formatting placeholders %1$s and %2$s.
+                        widgetClasses = widgetClasses.replace( /\S*%[12]\$s\S*/g, '' );
+                        widgetClasses = widgetClasses.replace( /^\s+|\s+$/g, '' );
+                        widgetSelector += '.' + widgetClasses.split( /\s+/ ).join( '.' );
                         self.widgetSelectors.push( widgetSelector );
                 });
         };