How to redirect user to the login screen when he returns the page through the browser nodejs

//Security middleware
app.use((req,res,next)=>{
	console.log('login')
	var path = parseurl(req).pathname	
	if(req.session){
		if(req.session.userId){
			var userId = req.session.userId						
			User.findOne({where:{id:userId}})
			.then((usr)=>{				
				req.user = usr.dataValues
				next()
			})
			.catch(err=>{
				res.redirect('/error')
			})			
		}else{			
			if(path != '/login' && path != '/error'){				
				res.redirect('/login')
			}else{								
				next()
			}			
		}
	}else{		
		next()
	}		
})

app.get('/error',(req, res)=>{
	res.send('Erro no banco de dados.')
})

app.get('/',(req, res, next)=>{	
	console.log(req.user)
	if(req.user){				
		res.render('home',{user:req.user})	
	}else{		
		res.render('login')
	}
	
})

app.get('/login',(req, res, next)=>{	
	if(req.user){				
		res.redirect('/')	
	}else{		
		res.render('login')
	}		
})

app.post('/login',(req, res, next)=>{
	username = req.body.username
	password = req.body.password
	User.findOne({where:{username:username,password:password}})
	.then( user =>{
		if(user){			
			req.session.userId = user.id			
			res.redirect('/')
		}else{
			console.log('Usuário nao encontrado.')
			res.redirect('/login')
		}	
	})
	.catch(err=>{
		console.log("db error")
		res.redirect('/error')
		next()
	})			
})

app.get('/logout',(req,res, next)=>{
	req.session.destroy(()=>{		
		res.redirect('/login')
	})
})