Gutenberg Gallery Block Refactor - Transform Back to Unordered List

gallery-block-transform-filter.php

function transform_new_gallery_block_to_unordered_list( $parsed_block ) {
	if ( $parsed_block['blockName'] === 'core/gallery' && strpos( $parsed_block['innerHTML'], 'has-nested-images' ) ) {
		forEach( $parsed_block['innerBlocks'] as &$value ) {
			$value['innerHTML'] = '<li class="blocks-gallery-item">' . $value['innerHTML'] . '</li>';
			$value['innerContent'][0] = '<li class="blocks-gallery-item">' . $value['innerContent'][0] . '</li>';
			$value['innerHTML'] = preg_replace( '/(class="wp-image-(\d+)")/', '$1 data-d="$2"', $parsed_block['innerHTML'] );
			$value['innerContent'][0] = preg_replace( '/(class="wp-image-(\d+)")/', '$1 data-id="$2"', $value['innerContent'][0] );
		}
		$parsed_block['innerHTML'] = preg_replace( '/(<figure.*>)/', '$1<ul ul class="blocks-gallery-grid">', $parsed_block['innerHTML'] );
		$parsed_block['innerHTML'] = preg_replace( '/<\/figure>/', '</ul></figure>', $parsed_block['innerHTML'] );
		$parsed_block['innerHTML'] = preg_replace( '/has-nested-images/', '', $parsed_block['innerHTML'] );

		$parsed_block['innerContent'][0] = preg_replace('/(<figure.*>)/', '$1<ul class="blocks-gallery-grid">', $parsed_block['innerContent'][0] );
		$parsed_block['innerContent'][0] = preg_replace('/<\/figure>/', '</ul></figure>', $parsed_block['innerContent'][0] );
		$parsed_block['innerContent'][0] = preg_replace('/has-nested-images/', '', $parsed_block['innerContent'][0] );
	}
	return $parsed_block;
}
add_filter( 'render_block_data', 'transform_new_gallery_block_to_unordered_list' );