WooCommerce 一張訂單限定一款商品

wc-only-one-item-in-one-order.php

<?php
add_filter( 'woocommerce_add_cart_item_data', 'mxp_wc_custom_add_to_cart' );
function mxp_wc_custom_add_to_cart( $cart_item_data ) {
        WC()->cart->empty_cart(true);
        WC()->session->set('cart', array());
        return $cart_item_data;
}