1 <?php

     2 /**

     3  * Appending the wp-block-heading to before rendering the stored `core/heading` block contents.

     4  *

     5  * @package WordPress

     6  */

     7 

     8 /**

     9  * Adds a wp-block-heading class to the heading block content.

    10  *

    11  * For example, the following block content:

    12  *  <h2 class="align-left">Hello World</h2>

    13  *

    14  * Would be transformed to:

    15  *  <h2 class="align-left wp-block-heading">Hello World</h2>

    16  *

    17  * @since 6.2.0

    18  *

    19  * @param array  $attributes Attributes of the block being rendered.

    20  * @param string $content Content of the block being rendered.

    21  *

    22  * @return string The content of the block being rendered.

    23  */

    24 function block_core_heading_render( $attributes, $content ) {

    25 	if ( ! $content ) {

    26 		return $content;

    27 	}

    28 

    29 	$p = new WP_HTML_Tag_Processor( $content );

    30 

    31 	$header_tags = array( 'H1', 'H2', 'H3', 'H4', 'H5', 'H6' );

    32 	while ( $p->next_tag() ) {

    33 		if ( in_array( $p->get_tag(), $header_tags, true ) ) {

    34 			$p->add_class( 'wp-block-heading' );

    35 			break;

    36 		}

    37 	}

    38 

    39 	return $p->get_updated_html();

    40 }

    41 

    42 /**

    43  * Registers the `core/heading` block on server.

    44  *

    45  * @since 6.2.0

    46  */

    47 function register_block_core_heading() {

    48 	register_block_type_from_metadata(

    49 		__DIR__ . '/heading',

    50 		array(

    51 			'render_callback' => 'block_core_heading_render',

    52 		)

    53 	);

    54 }

    55 

    56 add_action( 'init', 'register_block_core_heading' );