Remove usage of register_block_type as this isn't a block

mu-plugins/blocks/time/index.php

@@ -13,15 +13,26 @@
 add_action( 'init', __NAMESPACE__ . '\init' );
 
 /**
- * Registers the block using the metadata loaded from the `block.json` file.
- * Behind the scenes, it registers also all assets so they can be enqueued
- * through the block editor in the corresponding context.
- *
- * @see https://developer.wordpress.org/reference/functions/register_block_type/
+ * Enqueues the script for the Time format in the block editor using the metadata loaded from the `block.json` file,
+ * and adds the filter for transforming the time blocks.
  */
 function init() {
-	register_block_type( __DIR__ . '/build' );
-	add_filter('the_content', __NAMESPACE__ . '\transform_time_blocks', 99, 1);
+	// Add the JS script to add the Time formatting option to the toolbar. The dependencies are autogenerated in block.json,
+	// and can be read with `wp_json_file_decode` & `register_block_script_handle.
+	$metadata_file = __DIR__ . '/build/block.json';
+	$metadata = wp_json_file_decode( $metadata_file, array( 'associative' => true ) );
+	$metadata['file'] = $metadata_file;
+	$editor_script_handle = register_block_script_handle( $metadata, 'editorScript', 0 );
+	add_action(
+		'enqueue_block_assets',
+		function() use ( $editor_script_handle ) {
+			if ( wp_should_load_block_editor_scripts_and_styles() && is_admin() ) {
+				wp_enqueue_script( $editor_script_handle );
+			}
+		}
+	);
+
+	add_filter( 'the_content', __NAMESPACE__ . '\transform_time_blocks', 99, 1 );
 }
 
 /**
@@ -32,7 +43,7 @@ function init() {
  * @param string $content Post content.
  * @return string Content with display times reformatted.
  */
-function transform_time_blocks( $content) {
+function transform_time_blocks( $content ) {
 	if ( empty( $content ) ) {
 		return $content;
 	}
@@ -42,15 +53,15 @@ function transform_time_blocks( $content) {
 	$dom->loadHTML( $content );
 	$xpath = new \DOMXPath( $dom );
 	$time_elements = $xpath->query( "//*[contains(concat(' ', normalize-space(@class), ' '), ' wporg-time ')]" );
-	
+
 	foreach ( $time_elements as $time_element ) {
 		$time_content = $time_element->nodeValue;
 		$parsed_time = parse_time( $time_content );
 
 		if ( $parsed_time === null ) {
 			continue;
 		}
-		
+
 		// Build the link and abbr microformat.
 		$time_element->setAttribute( 'href', 'https://www.timeanddate.com/worldclock/fixedtime.html?iso=' . gmdate( 'Ymd\THi', $parsed_time ) );
 
@@ -77,13 +88,13 @@ function transform_time_blocks( $content) {
 function parse_time( $content ) {
 	// Replace non-breaking spaces with a regular white space.
 	$gmtcontent = preg_replace( '/\xC2\xA0| /', ' ', $content );
-	
+
 	// PHP understands "GMT" better than "UTC" for timezones.
 	$gmtcontent = str_replace( 'UTC', 'GMT', $gmtcontent );
-	
+
 	// Remove the word "at" from the string, if present. Allows strings like "Monday, April 6 at 19:00 UTC" to work.
 	$gmtcontent = str_replace( ' at ', ' ', $gmtcontent );
-	
+
 	// Try to parse the time, relative to the post time.
 	$time = strtotime( $gmtcontent, get_the_date( 'U' ) );