get_registered_fields example

/** * Retrieves the meta field value. * * @since 4.7.0 * * @param int $object_id Object ID to fetch meta for. * @param WP_REST_Request $request Full details about the request. * @return array Array containing the meta values keyed by name. */
    public function get_value( $object_id, $request ) {
        $fields   = $this->get_registered_fields();
        $response = array();

        foreach ( $fields as $meta_key => $args ) {
            $name       = $args['name'];
            $all_values = get_metadata( $this->get_meta_type(), $object_id, $meta_key, false );

            if ( $args['single'] ) {
                if ( empty( $all_values ) ) {
                    $value = $args['schema']['default'];
                } else {
                    $value = $all_values[0];
                }