Add modified to list of acceptable options for orderby param for the WooCommerce API

Add Support for Retreiving WooCommerce Orders By Modified Date

/ *
  Add modified to list of acceptable options for orderby param
  Allows you to fetch orders at /wp-json/wc/v3/orders/?orderby=modified&order=desc|asc
 */
add_filter( "rest_shop_order_collection_params", 'air_add_modified_to_param_validation',10);
function air_add_modified_to_param_validation($params){
    
    if(isset($params['orderby']) && isset($params['orderby']['enum']) && is_array($params['orderby']['enum']))
        $params['orderby']['enum'][] = "modified";

    return $params;
}