WC_Product_Variable::child_is_in_stock PHP Method

    public function child_is_in_stock()
    {
        $transient_name = 'wc_child_is_in_stock_' . $this->get_id();
        $in_stock = get_transient($transient_name);
        if (false === $in_stock) {
            $in_stock = $this->data_store->child_is_in_stock($this);
            set_transient($transient_name, $in_stock, DAY_IN_SECONDS * 30);
        }
        return (bool) $in_stock;
    }