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JavaScript User Authentication With Express and Mongo Improving the App with Custom Middleware Writing Custom Middleware

Robert Cooper
Robert Cooper
22,704 Points
Posted by Robert Cooper
Robert Cooper
22,704 Points

Unnecessary "if" statement conditional?

In the following code block, isn't it redundant to have req.session in addition to req.session.userId? If req.session.userId evaluates to true, that means that there is a session and req.session is also true.

function loggedOut(req, res, next) {
  if (req.session && req.session.userId) {
    return res.redirect('/profile');
  }
  return next();
}

1 Answer

Joe Beltramo
Joe Beltramo
Courses Plus Student 22,191 Points

In the code block provided, the use of req.session first is to prevent front a script error in checking an undefined property.

If req.session doesn't exist, it becomes unsafe to try and access a property against undefined. Essentially you would be doing this:

var request = undefined;

console.log(request.sessions.userId)

You wouldn't do this as request is not an object, nor does it have a property called session

Robert Cooper
Robert Cooper
22,704 Points
Robert Cooper
Robert Cooper
22,704 Points

Awesome, thanks for the explaining Joe. That makes a lot of sense.

Joe Beltramo
Joe Beltramo
Courses Plus Student 22,191 Points

Glad I could help :]