问ES6类:这是原型扩展另一个类的证明吗？

EN

class Menu {

  constructor(){}

  render(){
    this.addObjectsToStage();
  }

  addObjectsToStage() {
    var objects = this.objects.getAllObjects();
    for (var category in objects) {
      if (objects.hasOwnProperty(category)) {
        for (var type in objects[category]) {
          if (objects[category].hasOwnProperty(type))
            this.stage.addChild(objects[category][type]);
        }
      }
    }
  }

}

class MainMenu extends Menu{

  constructor(stage, options) {
    super();
    this.stage = stage;
    this.objects = new MenuObjects(options);
  }
}