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 */
24function 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 */
47function 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
56add_action( 'init', 'register_block_core_heading' );
57