ed_meta_keys( $object_type );
	if ( ! empty( $object_subtype ) ) {
		$meta_keys = array_merge( $meta_keys, get_registered_meta_keys( $object_type, $object_subtype ) );
	}

	return array_intersect_key( $data, $meta_keys );
}

/**
 * Filters out `register_meta()` args based on an allowed list.
 *
 * `register_meta()` args may change over time, so requiring the allowed list
 * to be explicitly turned off is a warranty seal of sorts.
 *
 * @access private
 * @since 5.5.0
 *
 * @param array $args         Arguments from `register_meta()`.
 * @param array $default_args Default arguments for `register_meta()`.
 * @return array Filtered arguments.
 */
function _wp_register_meta_args_allowed_list( $args, $default_args ) {
	return array_intersect_key( $args, $default_args );
}

/**
 * Returns the object subtype for a given object ID of a specific type.
 *
 * @since 4.9.8
 *
 * @param string $object_type Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',
 *                            or any other object type with an associated meta table.
 * @param int    $object_id   ID of the object to retrieve its subtype.
 * @return string The object subtype or an empty string if unspecified subtype.
 */
function get_object_subtype( $object_type, $object_id ) {
	$object_id      = (int) $object_id;
	$object_subtype = '';

	switch ( $object_type ) {
		case 'post':
			$post_type = get_post_type( $object_id );

			if ( ! empty( $post_type ) ) {
				$object_subtype = $post_type;
			}
			break;

		case 'term':
			$term = get_term( $object_id );
			if ( ! $term instanceof WP_Term ) {
				break;
			}

			$object_subtype = $term->taxonomy;
			break;

		case 'comment':
			$comment = get_comment( $object_id );
			if ( ! $comment ) {
				break;
			}

			$object_subtype = 'comment';
			break;

		case 'user':
			$user = get_user_by( 'id', $object_id );
			if ( ! $user ) {
				break;
			}

			$object_subtype = 'user';
			break;
	}

	/**
	 * Filters the object subtype identifier for a non-standard object type.
	 *
	 * The dynamic portion of the hook name, `$object_type`, refers to the meta object type
	 * (post, comment, term, user, or any other type with an associated meta table).
	 *
	 * Possible hook names include:
	 *
	 *  - `get_object_subtype_post`
	 *  - `get_object_subtype_comment`
	 *  - `get_object_subtype_term`
	 *  - `get_object_subtype_user`
	 *
	 * @since 4.9.8
	 *
	 * @param string $object_subtype Empty string to override.
	 * @param int    $object_id      ID of the object to get the subtype for.
	 */
	return apply_filters( "get_object_subtype_{$object_type}", $object_subtype, $object_id );
}