title: Fetch/React not redirecting with Node/Express res.redirect()
body: <p>On my React front-end, I make a fetch() GET call to my Node/Express server. The Node/Express server checks if response has a certain cookie, and if not should redirect it. My code is something like this:</p>
  
  <p>React code</p>
  
  <pre><code>componentDidMount(){
        fetch('/example',{redirect: "follow"})
        .then(data =&gt; data.json())
        .then(res =&gt; {
          //do something with response
           }
        })
     }
  </code></pre>
  
  <p>Node/Express:</p>
  
  <pre><code>router.use((req, res, next) =&gt; {
      let { token } = req.cookies;
  
      if(token){
          next();
      }
      else{
          res.redirect(303, '/login');
      }
  });
  
  router.get('/example', (req, res) =&gt;{
      //sends a json response back
  })
  </code></pre>
  
  <p>It might be important to note that I am using react-router-dom as a browser router, thought I'm not sure what this does to server redirects. I've searched and saw people who said to set redirect to "follow". However, even when setting status to a 3xx and setting redirect to "follow", the page still doesn't redirect properly. Instead, it receives a response with <code>200 OK status</code>(which I don't understand how it could have changed, unless Node/Express didn't actually set it to '303'), <code>redirected: true</code>, and a response.url pointing to the redirect url, but still stays on the same page. I've made sure that the cookie isn't there, so that's not it. I know I can probably check response.redirected every time and manually set window.location = response.url, but I still don't understand why the redirect did not work. Do I have to set it manually everytime then?</p>