The problem is not with TypeScript or even JavaScript but an odd Browser API where mutating some random value of an object results in a redirect on the page, but not synchronously.

Even if the language of the browser were Rust, there's nothing about the type system specifically that would have caught this bug (as far as I can tell, anyways. Presumably there's something in the background periodically reading the value of `href` and updating the page accordingly, but since that background job only would have needed read and not write access to the variable, I don't think the borrow checker would have helped here)