Extend native Date prototype without affecting the Date object

xdate.js

// based on http://stackoverflow.com/a/30882416/255239
function XDate() {
  // create new Date() with passed in args
  var date = new (Function.prototype.bind.apply(Date, [Date].concat(Array.prototype.slice.call(arguments))))
  date.__proto__ = XDate.prototype; // make XDate.prototype the inherited prototype of our Date instance. 
  return date;
}

XDate.prototype.__proto__ = Date.prototype; // inherit Date prototype so we can use Date methods

// example to show a new Date each time an instance is inspected
XDate.prototype.toString = function() {
  return (new Date()).toString()
};

// example
var date = new XDate()

setTimeout(function() {
  console.log('Date string is now: ', date) // logs a date that is ~1 second apart, not the date when date was created
}, 1000)