名前空間vendor \ module \ Helper;
クラスDataは\ Magento \ Framework \ App \ Helper \ AbstractHelper {
protected $_stockItemRepository;
protected $_scopeConfig;
protected $_storeScope;
public function __construct(\Magento\CatalogInventory\Model\Stock\StockItemRepository $_stockItemRepository, \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig)
{
    $this->_stockItemRepository = $_stockItemRepository;
    $this->_scopeConfig = $scopeConfig;
    $this->_storeScope = \Magento\Store\Model\ScopeInterface::SCOPE_STORE;
}
public function getIdsToLastStock($ids){
    if($this->_scopeConfig->getValue('module/vendor_module/active',$this->_storeScope)==1) {
        $products = array();
        $productIds = array();
        foreach ($ids as $id) {
            try {
                $stockItem = $this->_stockItemRepository->get($id);
                $products[] = array('id' => $id, 'stock' => $this->checkIfAvailableInStock($stockItem));
            } catch (\Exception $ex) {
                $products[] = array('id' => $id, 'stock' => 0);
            }
        }
        if (count($products) > 0) {
            foreach ($products as $id => $value) {
                $names[$id] = $value['stock'];
            }
            $keys = array_keys($products);
            array_multisort(
                $names, SORT_ASC, SORT_NUMERIC, $products, $keys
            );
            $result = array_combine($keys, $products);
            foreach ($result as $product) {
                $productIds[] = intval($product['id']);
            }
            return $productIds;
        } else {
            return $ids;
        }
    }
    return $ids;
}
private function checkIfAvailableInStock($item){
    if($item->getIsInStock()){
        if($item->getQty()>0)
            return 0;
    }
    return 1;
}
}