basketitem.php

<?php
 
 
namespace Bitrix\Sale\Rest\Synchronization\Loader;
 
 
class BasketItem extends Entity
{
    protected function getAdditionalFilterFileds()
    {
        $params = $this->getParams();
 
        if(isset($params['ORDER_ID']))
        {
            $filter = ['=ORDER_ID'=>$params['ORDER_ID']];
        }
        else
        {
            $filter = [];
        }
        return $filter;
    }
}