handing routes with query parameters

I am writing a node app with ExpressJs. I have to handle queries with the below formats:

http://hostname/path/states?sEcho=1&iColumns=8&iDisplayStart=0&iDisplayLength=10&mDataProp_0=vmName&sSearch_0=&bRegex_0=false&bSearchable_0=true&bSortable_0=true

I want to extract the request parameters inside my nodeJs app. I have configured the route like below:

/* GET Request. */
router.get('/states', function(req, res) {
  res.render('helloworld', { title: 'Hello, World!' })
});

How to extract the request parameters in NodeJs. I am very new to NodeJs. Please let me know. I am struck on this..