Restricting cart items to be from the same product category in WooCommerce

Question

I am using the code below to remove other WooCommerce product category items from the cart when there is an item with a special product category \'cat_x\' added in cart and

Answer 1

Making a custom function hooked in woocommerce_add_to_cart_validation filter hook is going to do the job in a much more simpler way, without any need to set an array of categories.

So your code will be much more faster and compact. Additionally you can display a custom notice to warn the customer.

This code will avoid adding to cart, if an item of a different category is in cart:

add_filter( 'woocommerce_add_to_cart_validation', 'add_to_cart_validation_callback', 10, 3 );
function add_to_cart_validation_callback( $passed, $product_id, $quantity) {
    // HERE set your alert text message
    $message = __( 'MY ALERT MESSAGE.', 'woocommerce' );

    if( ! WC()->cart->is_empty() ) {
        // Get the product category terms for the current product
        $terms_slugs = wp_get_post_terms( $product_id, 'product_cat' array('fields' => 'slugs'));

        // Loop through cart items
        foreach (WC()->cart->get_cart() as $cart_item ){
            if( ! has_term( $terms_slugs, 'product_cat', $cart_item['product_id'] )) {
                $passed = false;
                wc_add_notice( $message, 'error' );
                break;
            }
        }
    }
    return $passed;
}

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code is tested and it works

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Restricting cart items to be only from different product categories:

Replace in the function the condition:

if( ! has_term( $product_cats, 'product_cat', $cart_item['product_id'] )) { 

by

if( has_term( $product_cats, 'product_cat', $cart_item['product_id'] )) {

Answer 2

I just tried and i got a syntax error the array that i fixed this way:

$terms_slugs = wp_get_post_terms($product_id, 'product_cat', array('fields' => 'slugs'));

just a comma after product_cat distraction, but maybe somebody would need it.