How to implement checking the repost of a VKontakte community post from a widget on a third-party site?

Question

JavaScript

Good day everyone!
The situation is as follows - the site has a VK widget "Write on the community wall", in which all elements are hidden except for the "Tell friends" button, below is the order button. The task is to check likes.isLiked for repost (if copied = 'true') on this site when you click on the order button and recalculate the cost of the order.
I understand that the likes.isLiked method does not apply to OpenAPI and it cannot be called from a third-party domain, or am I wrong?