test.js

(function () {
  var now = typeof performance !== 'undefined' ? performance.now.bind(performance) : Date.now;

  function Accessor() {
    var obj = { }
    obj.x = 0;
    delete obj.x;
  
    var _a = 0;
    Object.defineProperty(obj, 'a', {
      enumerable: true,
      get: function () { return _a; },
      set: function(val) { _a = val; }
    });
  
    var sum = 0;
    var start = now();
    for (var i = 0; i < 1000000; i++) {
      sum += obj.a;
      obj.a = i;
    }
    var end = now();
    return (end - start);
  }
  
  function KindaAccessor() {
    var obj = { }
    obj.x = 0;
    delete obj.x;
  
    var _a = 0;
    obj.a = {
      get: function () { return _a; },
      set: function(val) { _a = val; }
    };
  
    var sum = 0;
    var start = now();
    for (var i = 0; i < 1000000; i++) {
      sum += obj.a.get();
      obj.a.set(i);
    }
    var end = now();
    return (end - start);
  }
  
  for (var i = 0; i < 10; i++) {
    Accessor();
    KindaAccessor();
  }

  if (Accessor()/KindaAccessor() > 2 * Math.PI) {
    alert("(ಥ﹏ಥ) this VM could handle accessors much better");
  } else if (Accessor()/KindaAccessor() > Math.E) {
    alert("(ಠ_ಠ) this VM could handle accessors better");
  }
})();