Block/Js.php
public function getMagentoStoreId()
    {
        if ($this->checkoutSession instanceof BackendSessionQuote) {
            $quote = $this->checkoutSession;
        } else {
            $quote = $this->checkoutSession->getQuote();
        }

        return (int) (($quote && $quote->getStoreId()) ?
            $quote->getStoreId() : 0);
    }
public function getMagentoStoreId()
    {
        if ($this->checkoutSession instanceof BackendSessionQuote) {
            $quote = $this->checkoutSession;
        } else {
            $quote = $this->checkoutSession->getQuote();
        }

        return (int) (($quote && $quote->getStoreId()) ?
            $quote->getStoreId() : 0);
    }
public function getMagentoStoreId ( ) { if ( $ this -> checkoutSession instanceof BackendSessionQuote ) { $ quote = $ this -> checkoutSession ; } else { $ quote = $ this -> checkoutSession -> getQuote ( ) ; } return ( int ) ( ( $ quote && $ quote -> getStoreId ( ) ) ? $ quote -> getStoreId ( ) : 0 ) ; }
If we have multi-website, we need current quote store_id

@return int
If we have multi - website we need current quote store_id