Code-Snippets-Functions/Execute a function on a child site/WooCommerce/keep-the-last-added-item-in-cart.txt

add_action( 'woocommerce_before_calculate_totals', 'keep_only_last_cart_item', 30, 1 );
function keep_only_last_cart_item( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    $cart_items = $cart->get_cart();

    if( count( $cart_items ) > 1 ){
        $cart_item_keys = array_keys( $cart_items );
        $cart->remove_cart_item( reset($cart_item_keys) );
    }
}