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<?php
/**
 * allowed blocks type
 * Block List: https://en.support.wordpress.com/wordpress-editor/blocks/
 *
 * @param bool|array $allowed_block_types Array of block type slugs, or
 * @param object The post resource data.
 */
function filter_allowed_block_types( $allowed_block_types, $post ) {
  // echo '<pre>';
  // var_dump($allowed_block_types);
  // echo '</pre>';
  switch ($post->post_type) {
    case 'custom_post':
      $allowed_block_types = [
        'core/paragraph',
      ];
      break;
    default:
      $allowed_block_types = [
        'core/paragraph',
        'core/heading',
        'core/image',
        'core-embed/youtube'
      ];
  }
  return $allowed_block_types;
}
add_filter( 'allowed_block_types', 'filter_allowed_block_types', 10, 2 );