title: "Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client" when trying to redirect
body: <p>i am trying to set a cookie if a person enters the correct key (1234) but when they type in the correct key it spits out an error </p>
  
  <p>Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client</p>
  
  <p>idk what to do i tried to redirect before setting the cookie and even just logging after the redirect but the error doesn't go away!</p>
  
  <p>heres my code:
  key is defined just not in this part</p>
  
  <pre><code>app.get("/", function(req,res) {
      if (req.cookies.userSecret == key) {
      res.sendFile(__dirname + "/index.html");
      } else {
          res.sendFile(__dirname + "/login.html")
          io.on("connection", function(socket) {
              socket.on("login", function(data){
                  if (data == key) {
                      res.redirect("/1799fd8e-78aa-4bc0-9692-011a81c07248")
                      return false;
                  } else {
                      io.emit("log", "Wrong key! try again")
                      return false;
                  }
              })
          })
      }
  });
  
  app.get("/1799fd8e-78aa-4bc0-9692-011a81c07248", function(req,res) {
      console.log(key)
      res.sendFile(__dirname + "/index.html")
  })
  </code></pre>