[AngularJS] Store the entry url and redirect to entry url after Logged in

For example when a outside application need to visit your app address:

https://www.example.com/#/lobby/abc

But before enter '/lobby/abc', user need to login, so the application will redirect user to 

https://www.example.com/#/login

Now what you want is after user logged in, you can redirect them to 

https://www.example.com/#/lobby/abc

Instead of other pages like:

https://www.example.com/#/lobby

So to solve the problem, we need to do two things

1. Store the entry url

2. After logged in, redirect user to entry url

1. Store the entry ur:

angular.module('app')
     // When can get pull url by using $location.absUrl()
    // Because run block only run once for the module and app module is our main application module, so this should only store our entry url
    // To reuse the entryUrl later, we store it in LoginService
    .run(($location, LoginService) => LoginService.entryUrl = $location.absUrl())

2. After logged in, then we can redirect user to the entry url by doing:

$location.url(LoginService.entryUrl)