Sample block Parser

class-sample-block-parser.php

<?php
/**
 * Class: Sample_Block_Parser
 *
 * @package Sample
 * @subpackage sample-project
 * @since 1.0.0
 */

add_filter(
	'block_parser_class',
	function() {
		return __NAMESPACE__ . '\\Sample_Block_Parser';
	}
);

/***
 * Specialized block serialization parser
 */
class Sample_Block_Parser extends \WP_Block_Parser {

	/**
	 * Blocks that could be last
	 *
	 * @var array
	 */
	public static $allowed_inner_blocks = [
		// Classic blocks have their blockName set to null.
		null,
		'core/freeform',
		'core/heading',
		'core/html',
		'core/list',
		'core/media-text',
		'core/paragraph',
		'core/preformatted',
		'core/pullquote',
		'core/quote',
		'core/table',
		'core/verse',
		'core/columns',
	];

	/**
	 * Parse document to get a list of block structures
	 *
	 * @param string $document  Input document being parsed.
	 */
	public function parse( $document ) {
		$this->document    = $document;
		$this->offset      = 0;
		$this->output      = array();
		$this->stack       = array();
		$this->empty_attrs = json_decode( '{}', true );
		// phpcs:disable Generic.CodeAnalysis.EmptyStatement
		do {
			// twiddle our thumbs.
		} while ( $this->proceed() );
		// phpcs:enable

		return $this->process_output();
	}

	/**
	 * Put Article tags at the end
	 */
	public function process_output() {

		$last_block_key = 0;
		$article_tags   = sample_article_tags();

		if ( ! is_array( $this->output ) ) {
			return $this->output;
		}

		foreach ( $this->output as $index => $block ) {
			if ( ! isset( $block['blockName'] ) ) {
				continue;
			}

			if ( in_array( $block['blockName'], self::$allowed_inner_blocks, true ) ) {
				$last_block_key = $index + 1;
			}
		}

		if ( $last_block_key ) {
			$this->output[ $last_block_key ]['innerHTML']       = $article_tags . $this->output[ $last_block_key ]['innerHTML'];
			$this->output[ $last_block_key ]['innerContent'][0] = $article_tags . $this->output[ $last_block_key ]['innerContent'][0];

		}

		return $this->output;
	}
}