bnb.js

function BadNewsBears() {
  var a = 0;
  Object.defineProperty(this,
                        'inc', 
                        {
                          get : function () { return a++; },
                          enumerable : true
                        });
}

BadNewsBears.prototype.wtf = function () {
  var b = (this.inc, this.inc, this.inc);
  return b;
}

var lol = new BadNewsBears();
lol.wtf() // --> ?