I would recommend to use Passport or Satellizer (for AngularJS) for your authentication. If you decide to use Passport, you can use passport-twitch, it’s an unofficial Twitch strategy for Passport that I created a few years ago. I never tried Satellizer to be honest, but I heard really good things about it if you are using AngularJS.
Edit: Passport will let you redirect the user to a page using successRedirect and failureRedirect. You can keep the link that you want your user to be redirected to using connect-flash or express-session… This is pretty much up to you 