Refactor: Use null coalescing operator for improved readability (WordPress#76777)

Co-authored-by: Soean <soean@git.wordpress.org>
Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>

Author: 3 people

lib/experimental/content-guidelines/class-gutenberg-content-guidelines-post-type.php

@@ -241,7 +241,7 @@ public static function get_guideline_categories_from_meta( $post_id ) {
 		foreach ( $all_meta as $meta_key => $meta_values ) {
 			if ( self::is_block_meta_key( $meta_key ) ) {
 				$block_name = self::meta_key_to_block_name( $meta_key );
-				$value      = isset( $meta_values[0] ) ? $meta_values[0] : '';
+				$value      = $meta_values[0] ?? '';
 
 				if ( ! empty( $value ) ) {
 					$blocks[ $block_name ] = array(

lib/experimental/content-guidelines/class-gutenberg-content-guidelines-rest-controller.php

@@ -391,9 +391,7 @@ protected function save_guideline_categories_to_meta( $post_id, $categories ) {
 		foreach ( Gutenberg_Content_Guidelines_Post_Type::CATEGORY_META_KEYS as $category ) {
 			if ( isset( $categories[ $category ] ) ) {
 				$meta_key = '_content_guideline_' . $category;
-				$value    = isset( $categories[ $category ]['guidelines'] )
-					? $categories[ $category ]['guidelines']
-					: '';
+				$value    = $categories[ $category ]['guidelines'] ?? '';
 				update_post_meta( $post_id, $meta_key, $value );
 			}
 		}
@@ -402,7 +400,7 @@ protected function save_guideline_categories_to_meta( $post_id, $categories ) {
 		if ( isset( $categories['blocks'] ) && is_array( $categories['blocks'] ) ) {
 			foreach ( $categories['blocks'] as $block_name => $block_data ) {
 				$meta_key = Gutenberg_Content_Guidelines_Post_Type::block_name_to_meta_key( $block_name );
-				$value    = isset( $block_data['guidelines'] ) ? $block_data['guidelines'] : '';
+				$value    = $block_data['guidelines'] ?? '';
 
 				if ( ! empty( $value ) ) {
 					update_post_meta( $post_id, $meta_key, $value );