Exclude external products

This plugin is clean and works great. One thing I would suggest in the code. there should be a check for whether the product is external otherwise it tries to add it to cart but nothing ever happens. In the add_product_js function add this code to accomplish:

global $post;
if (function_exists(‘wc_get_product’)):
$product = wc_get_product($post->ID);
if (function_exists(‘is_product’) && is_product() && !$product->is_type(‘external’)) {
wp_enqueue_script(‘woo-ajax-add-to-cart’);
}
endif;

good luck and thanks.