If the navigation simulates what would happen if we follow links to SPA#pos1, SPA#pos2, etc so that if I do two clicks within the SPA, and then hit Back three times I'm back to whatever link I followed to get to the SPA, I guess it's OK and follows user expectations. But if it is used as an excuse to trap the user in the SPA unless they kill the tab, not OK.
> From the browsers perspective those are the same thing though.
If the browser only allows adding at most one history item per click, I should be able to go back to where I entered a given site with at most that many back button clicks.
At a first glance, this doesn't seem crazy hard to implement? I'm probably missing some edge cases, though.
Some browser APIs (such as playing video) are locked behind a user interaction. Do the same for the history API: make it so you can't add any items to history until the user clicks a link, and then you can only add one.
That's not perfect, and it could still be abused, but it might prevent the most common abuses.
