Thêm nút Mua ngay cho Woocommerce

/*
* Add quick buy button go to checkout after click
*/
add_action('woocommerce_after_add_to_cart_button','devvn_quickbuy_after_addtocart_button');
function devvn_quickbuy_after_addtocart_button(){
    global $product;
    ?>
    <style>
        .devvn-quickbuy button.single_add_to_cart_button.loading:after {
            display: none;
        }
        .devvn-quickbuy button.single_add_to_cart_button.button.alt.loading {
            color: #fff;
            pointer-events: none !important;
        }
        .devvn-quickbuy button.buy_now_button {
            position: relative;
            color: rgba(255,255,255,0.05);
        }
        .devvn-quickbuy button.buy_now_button:after {
            animation: spin 500ms infinite linear;
            border: 2px solid #fff;
            border-radius: 32px;
            border-right-color: transparent !important;
            border-top-color: transparent !important;
            content: "";
            display: block;
            height: 16px;
            top: 50%;
            margin-top: -8px;
            left: 50%;
            margin-left: -8px;
            position: absolute;
            width: 16px;
        }
    </style>
    <button type="button" class="button buy_now_button">
        <?php _e('Mua ngay', 'devvn'); ?>
    </button>
    <input type="hidden" name="is_buy_now" class="is_buy_now" value="0" autocomplete="off"/>
    <script>
        jQuery(document).ready(function(){
            jQuery('body').on('click', '.buy_now_button', function(e){
                e.preventDefault();
                var thisParent = jQuery(this).parents('form.cart');
                if(jQuery('.single_add_to_cart_button', thisParent).hasClass('disabled')) {
                    jQuery('.single_add_to_cart_button', thisParent).trigger('click');
                    return false;
                }
                thisParent.addClass('devvn-quickbuy');
                jQuery('.is_buy_now', thisParent).val('1');
                jQuery('.single_add_to_cart_button', thisParent).trigger('click');
            });
        });
    </script>
    <?php
}
add_filter('woocommerce_add_to_cart_redirect', 'redirect_to_checkout');
function redirect_to_checkout($redirect_url) {
    if (isset($_REQUEST['is_buy_now']) && $_REQUEST['is_buy_now']) {
        $redirect_url = wc_get_checkout_url(); //or wc_get_cart_url()
    }
    return $redirect_url;
}