WooCommerce Limit Cart to 1 Product

snippet.php

/**
 * @snippet       WooCommerce Max 1 Product @ Cart
 * @how-to        Get CustomizeWoo.com FREE
 * @author        Rodolfo Melogli
 * @compatible    WCooCommerce 7
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 * Note: technically speaking, the code below will force the product added to cart to replace whatever 
 * is in the cart, hence will only allow one product in the cart.
 * Ref: https://www.businessbloomer.com/woocommerce-allow-1-product-cart/
 */
  
 add_filter( 'woocommerce_add_to_cart_validation', 'bbloomer_only_one_in_cart', 9999 );
   
 function bbloomer_only_one_in_cart( $passed ) {
    wc_empty_cart();
    return $passed;
 }