title: Protected routes for react with a express backend protected by passport
body: <p>I am a little confused and the more I read, the more confused I get...</p>
  <p>So I have an JS Express Backend that is protected by a PassportJS local Strategy and uses express-session. How would I proceed within my React Set Up now? Can I just make a route on my server, that checks whether the User is logged in or not, and then depending on the response set a React State accordingly, which  allows access to protected routes?
  I assume all redirecting (for example for unauthorised request to a route) then takes place in the react app and not from the server (for example res.redirect()?</p>
  <p>I am very new to React and web development, so I am a little confused about security here, because I thought all React-Front-End JS is accessible to the client!</p>