title: How to make an Angular 5 + Node app with CAS authentication?
body: <p>I'm currently trying to build an app that needs the user to authenticate with CAS (Centrale Authentication Service) to use it. I'm using Angular 5 for the front-end and Node.js for the back-end.</p>
  
  <p>To authenticate the user on the server side I'm using a module called 'r-cas-authentication' which creates an express-session when the user is authenticated. The fact is I don't know how to check on the Angular side if the user is authenticated and otherwise redirect him on the CAS authentication page.</p>
  
  <p>Do you know how I could do that?
  Thanks!</p>