Node.js V8 pass by reference

I wonder how memory is managed in V8. Take a look at this example:

function requestHandler(req, res){
  functionCall(req, res);
  secondFunctionCall(req, res);
  thirdFunctionCall(req, res);
  fourthFunctionCall(req, res);
};

var http = require('http');
var server = http.createServer(requestHandler).listen(3000);

The req and res variables are passed in every function call, my question is:

1. Does V8 pass this by reference or does it make a copy in memory?

2. Is it possible to pass variables by reference, look at this example.

   var args = { hello: 'world' };
   
   function myFunction(args){
     args.newHello = 'another world';
   }
   
   myFunction(args);
   console.log(args);
   

   The last line, console.log(args); would print:

   "{ hello: 'world', newWorld: 'another world' }"
   

Thanks for help and answers :)