The app.use function encountered an error stating "Cannot modify header information - headers already sent"

Within my app.js file, I have the following code snippet:

app.use(function(req, res, next){

  if(!req.user){
    res.redirect('/login_');
  }
  next();
})

Upon reviewing the above code, everything appears to be correct. In my route/index.js file, I have the following code block:

router.get('/login_', function(req, res) {
    res.render('login', { user : req.user });
});

Despite my efforts, I encountered an error message stating:

throw new Error('Can\'t set headers after they are sent.')
. Although I understand that this error typically occurs when a response has already been sent and the request continues, I am unsure what is wrong with my code above. I am seeking guidance on how to resolve this issue.

If interested, here is the complete code from route/index.js: http://pastebin.com/kT2QfnjL

Answer №1

The reason for this issue is that the code attempts to send a response after it has already been sent.

For more information, you can check out:

Error: Can't set headers after they are sent to the client

Answer №2

res.send and navigate to address the problem

app.use(function(req, res, next){

  if(!req.user){
    return res.redirect('/login_');
  }
  next();
})

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