noSuchMethod / methodMissing -ish interface in vanilla javascript

uglyNoSuchMethod.js

var Foo = function Foo() {
  var someValue = 1;

  this.noSuchMethodHandler(id, args) {
    if (id == "increment") {
      return someValue++;
    }
  }
};
Foo.prototype.exec = function(id,args) {
  if (this[id] && (typeof this[id]=="function")) {
    return this[id](args);
  } else {
    // noSuchMethod
    return this.noSuchMethodHandler(id,args);
  }
}

var k = new Foo();
k.exec("increment"); // 1
k.exec("increment"); // 2
k.exec("increment"); // 3