title: What is conceptual best practice for express req.locals vs res.locals?
body: <p>It seems like from a conceptual perspective the request is what is propogating through the middle ware until it reaches the final middleware (which is named after the request type: app.get, app.post) then the request is terminated and the response begins inside of the final middleware.  </p>
  
  <p>NOW the response object is created...and includes any response variables and the view?</p>
  
  <p>Does the request end at the apps entry point or at the final middleware?</p>
  
  <p>Are we building the response object or the request object in the intermediate middlewares?  </p>
  
  <p>Or are they both passed through in parallel and it really doesn't matter?</p>
  
  <p>Here's a similar question but doesn't answer it to my satisfaction.</p>
  
  <p><a href="https://stackoverflow.com/questions/33451053/req-locals-vs-res-locals-vs-res-data-vs-req-data-vs-app-locals-in-express-mi">req.locals vs. res.locals vs. res.data vs. req.data vs. app.locals in Express middleware</a></p>