Code Modernization: Customize: Use null coalescing operator instead of isset() ternaries.

Developed as a subset of #10654
Initially developed in #4886

Follow-up to [61432], [61431], [61430], [61429], [61424], [61404], [61403].

Props costdev, westonruter.
See #58874, #63430.


git-svn-id: https://develop.svn.wordpress.org/trunk@61433 602fd350-edb4-49c9-b593-d223f7449a82

Author: westonruter

src/wp-includes/class-wp-customize-nav-menus.php

@@ -1251,7 +1251,7 @@ protected function print_post_type_container( $available_item_type ) {
 						</div>
 					<?php endif; ?>
 				<?php endif; ?>
-				<ul class="available-menu-items-list" data-type="<?php echo esc_attr( $available_item_type['type'] ); ?>" data-object="<?php echo esc_attr( $available_item_type['object'] ); ?>" data-type_label="<?php echo esc_attr( isset( $available_item_type['type_label'] ) ? $available_item_type['type_label'] : $available_item_type['type'] ); ?>"></ul>
+				<ul class="available-menu-items-list" data-type="<?php echo esc_attr( $available_item_type['type'] ); ?>" data-object="<?php echo esc_attr( $available_item_type['object'] ); ?>" data-type_label="<?php echo esc_attr( $available_item_type['type_label'] ?? $available_item_type['type'] ); ?>"></ul>
 			</div>
 		</div>
 		<?php

src/wp-includes/class-wp-customize-setting.php

@@ -941,7 +941,7 @@ final protected function multidimensional_replace( $root, $keys, $value ) {
 	 */
 	final protected function multidimensional_get( $root, $keys, $default_value = null ) {
 		if ( empty( $keys ) ) { // If there are no keys, test the root.
-			return isset( $root ) ? $root : $default_value;
+			return $root ?? $default_value;
 		}
 
 		$result = $this->multidimensional( $root, $keys );

src/wp-includes/class-wp-customize-widgets.php

@@ -924,7 +924,7 @@ public function output_widget_control_templates() {
 					<span class="customize-action">
 						<?php
 						$panel       = $this->manager->get_panel( 'widgets' );
-						$panel_title = isset( $panel->title ) ? $panel->title : __( 'Widgets' );
+						$panel_title = $panel->title ?? __( 'Widgets' );
 						/* translators: &#9656; is the unicode right-pointing triangle. %s: Section title in the Customizer. */
 						printf( __( 'Customizing &#9656; %s' ), esc_html( $panel_title ) );
 						?>
@@ -1123,7 +1123,7 @@ public function get_available_widgets() {
 			$available_widget = array_merge(
 				$available_widget,
 				array(
-					'temp_id'      => isset( $args['_temp_id'] ) ? $args['_temp_id'] : null,
+					'temp_id'      => $args['_temp_id'] ?? null,
 					'is_multi'     => $is_multi_widget,
 					'control_tpl'  => $control_tpl,
 					'multi_number' => ( 'multi' === $args['_add'] ) ? $args['_multi_num'] : false,

src/wp-includes/customize/class-wp-customize-header-image-setting.php

@@ -40,8 +40,8 @@ public function update( $value ) {
 		if ( empty( $custom_image_header ) ) {
 			require_once ABSPATH . 'wp-admin/includes/class-custom-image-header.php';
 			$args                   = get_theme_support( 'custom-header' );
-			$admin_head_callback    = isset( $args[0]['admin-head-callback'] ) ? $args[0]['admin-head-callback'] : null;
-			$admin_preview_callback = isset( $args[0]['admin-preview-callback'] ) ? $args[0]['admin-preview-callback'] : null;
+			$admin_head_callback    = $args[0]['admin-head-callback'] ?? null;
+			$admin_preview_callback = $args[0]['admin-preview-callback'] ?? null;
 			$custom_image_header    = new Custom_Image_Header( $admin_head_callback, $admin_preview_callback );
 		}
 

src/wp-includes/customize/class-wp-customize-nav-menu-item-setting.php

@@ -252,7 +252,7 @@ public function value() {
 		// These properties are read-only and are part of the setting for use in the Customizer UI.
 		if ( is_array( $value ) ) {
 			$value_obj               = (object) $value;
-			$value['type_label']     = isset( $type_label ) ? $type_label : $this->get_type_label( $value_obj );
+			$value['type_label']     = $type_label ?? $this->get_type_label( $value_obj );
 			$value['original_title'] = $this->get_original_title( $value_obj );
 		}