creating authentication function node.js

Question

I have this beautiful way of checking if someone is authenticated using express-session. Here is how:

if (req.session.loggedin) {

... do code ...

} else {
    req.session.destory;
    res.redirect('/login')
}

however, I want to create some sort of middleware maybe, or a call to the function everything another function is called. Like this.

function auth (req, res) {
   if (req.session.loggedin) {

        return;

   } else {
    req.session.destory;
    res.redirect('/login')
   }

}

app.get('/home', (req, res) => {
  auth()
... do code ...

}) 

or :

app.get('/home', (req, res, auth) => {
... do code ...
})

is this possible, if so, how do I do it?

Answer 1

Make auth middleware with validating session, remember call next function when any is good.

function auth(req, res, next) {
   if (req.session.loggedin) {
       return next(); // call next function to go to next handler
   } else {
      req.session.destory;
      res.redirect('/login')
   }
}

Then, apply the middleware for each router that requires authentication:

app.get('/home', auth, (req, res) => { // apply auth before "do code"
   // ... do code ...
})