<a class="active" href="/dashboard">
   <i class="fa fa-dashboard">
  </i><span>Dashboard</span>
  </a>

router.get('/dashboard/',function(req,res,next){
   res.render('dashboard');
});

<a class="active" href="/dashboard/dashboardcontent">
   <i class="fa fa-dashboard">
  </i><span>Dashboard</span>
  </a>

router.get('/dashboard/dashboardcontent',function(req,res,next){
   res.render('dashboard');
});