Check if the product is pre-order on product-page

Hi Yith,

Great plugin you have created. I was wondering if there is any way to check in the code if a product is pre-order. Like it is with variable products, I was thinking something like this:

if($product->is_type( ‘pre-order’ ) ):
Do something

Is there any field I can use to check if the product is pre-order?

Kind regards Morten