Customize: Trim whitespace from nav menu item titles so that the underlying object's original title appears as input placeholder and in the control's title.

Whitespace is trimmed from titles in PHP when saved in any case, so this aligns the client-side behavior with what happens on the server.

Amends [38618].
See #38015.
Fixes #39600.

Built from https://develop.svn.wordpress.org/trunk@39994


git-svn-id: http://core.svn.wordpress.org/trunk@39931 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/customize-nav-menus.js

@@ -1518,22 +1518,29 @@
 		 * Update item handle title when changed.
 		 */
 		_setupTitleUI: function() {
-			var control = this;
+			var control = this, titleEl;
 
+			// Ensure that whitespace is trimmed on blur so placeholder can be shown.
+			control.container.find( '.edit-menu-item-title' ).on( 'blur', function() {
+				$( this ).val( $.trim( $( this ).val() ) );
+			} );
+
+			titleEl = control.container.find( '.menu-item-title' );
 			control.setting.bind( function( item ) {
+				var trimmedTitle, titleText;
 				if ( ! item ) {
 					return;
 				}
+				trimmedTitle = $.trim( item.title );
 
-				var titleEl = control.container.find( '.menu-item-title' ),
-				    titleText = item.title || item.original_title || api.Menus.data.l10n.untitled;
+				titleText = trimmedTitle || item.original_title || api.Menus.data.l10n.untitled;
 
 				if ( item._invalid ) {
 					titleText = api.Menus.data.l10n.invalidTitleTpl.replace( '%s', titleText );
 				}
 
 				// Don't update to an empty title.
-				if ( item.title || item.original_title ) {
+				if ( trimmedTitle || item.original_title ) {
 					titleEl
 						.text( titleText )
 						.removeClass( 'no-title' );