I'm building a single page application and i'm using a client-side routing library to handle url/state changes.
Let's say googlebot visits example.com/my-shop-name/menu, the menu-items for my-shop-name are loaded dynamically and a url parameter is immediately appended to the url like so: example.com/my-shop-name/menu?top_item=some_item_id. top_item represents the item in a list of menu-items on the page that is currently at the top of the viewport. As the user scrolls, this parameter will naturally update as the top-most item changes. The point of this parameter is to remember the scroll position. It should also be pointed out that whenever the parameter is updated in the url, the page never reloads.
My first question is: what url will be indexed?
Secondly, if the latter is indexed, will instructing the web crawlers to ignore top_item as a url parameter in robots.txt make it so the first url is indexed and the latter is not?