Load regular price (for on sale) strikeout in product page

Load regular price strikeout (for on-sale items) on the product page.

if(!function_exists('woo_discount_rules_price_strikeout_before_discount_price_method')){
    function woo_discount_rules_price_strikeout_before_discount_price_method($item_price, $product){
        $regular_price = $product->get_regular_price();
        $item_price = wc_price($regular_price).$product->get_price_suffix();
        return $item_price;
    }
}

add_filter('woo_discount_rules_price_strikeout_before_discount_price', 'woo_discount_rules_price_strikeout_before_discount_price_method', 10, 2);