There are endless ways this can be approached. It also depends on how your application is designed.
If your application starts with a login page, wait for the server response and only proceed to your main application page only if they input valid credentials.
If your application displays your main application page upon boot, you can keep track of their login status using a simple flag in your scope. Whenever the user wants to navigate, check this flag and if they are not logged in, do not let them proceed.