Kludgey monkey-patched ES6 UTC-enabled Date()

date.js

// Do not use if you need something else from Date
// This only naively looks for a date with the format YYYY-MM-DD
// No other cases are covered or guaranteed to still work
// This is just a demo

// Save the old Date thing
var _Date = Date;

// Override the native Date thing
Date = function (string) {
  var newDateString;
  var plainDateRe = /[0-9]{4}-[0-9]{2}-[0-9]{2}$/;
  if (string.match(plainDateRe) != null) {
    newDateString = string + ' 00:00:00 GMT';
  } else {
    newDateString = string;
  }
  return new _Date(newDateString);
}

// Test:
var d = new Date('2015-10-10');
d.toString(); // Should output local time