One WooCommerce AJAX call always timing out after 5 seconds

As noted by the comments on the first question, the cancellation doesn’t timeout, it get’s cancelled, which means, that we can safely assume, that it happens on the client-side.

So I searched for somewhere this timeout is set on the client side, and as of woocommerce 8.3.0, in wp-content/plugins/woocommerce/includes/class-wc-frontend-scripts.php you have a method called get_script_data($handle), which includes a case for wc-cart-fragments:

case 'wc-cart-fragments':
    $params = array(
        'ajax_url'        => WC()->ajax_url(),
        'wc_ajax_url'     => WC_AJAX::get_endpoint('%%endpoint%%'),
        'cart_hash_key'   => apply_filters('woocommerce_cart_hash_key', 'wc_cart_hash_' . md5(get_current_blog_id() . '_' . get_site_url(get_current_blog_id(), '/') . get_template())),
        'fragment_name'   => apply_filters('woocommerce_cart_fragment_name', 'wc_fragments_' . md5(get_current_blog_id() . '_' . get_site_url(get_current_blog_id(), '/') . get_template())),
        'request_timeout' => 5000,
    );
    break;

Which has 'request_timeout' => 5000,

Be aware that this is probably a performance parameter set by woocommerce intentionally, so the best solution is still to fix your site’s responsiveness. However, if you want to change it, I have two suggestions:

1. Since I only experience this during development, I have just modified the file directly on my local wordpress instance. In this case I won’t accidentally push the code to production.
2. If you actually need to change this timeout setting, you should do it through a filter instead. In the end of the above method, you have a line return apply_filters('woocommerce_get_script_data', $params, $handle);, so you can add a filter like this:

add_filter('woocommerce_get_script_data', 'custom_woocommerce_get_script_data', 10, 2);
function custom_woocommerce_get_script_data($params, $handle)
{
    if ($handle === 'wc-cart-fragments') {
        $params['request_timeout'] = 10000;
    }
    return $params;
}