It is not documented that i can construct a relative path of a subpage with path(string).
Let the current page to be #/first
to construct a #/first/alert
If so, why it is not documented?
It seems like I got some copy-n-paste bug in the documentation. The page Path should really document this feature but is instead documenting the find-method. I'll fix it. Thanks for the heads up.
Regarding your second question I would say it depends on your current context. Sometimes your solution is the best, sometimes you might be able to navigate in some other way. Internally (in pager.js) I'm usually doing something similar to your code example.