const App = console.log.bind(null, 'Hello')

    Object.defineProperty(window, 'App', {

      set: ()=> {

        console.error("You are not allow to modify App");

      }

    })

    const sandbox = (App, Function, window) => {

      'use strict';

      function a() {

        'use strict';

        // *** I can only modify codes within this block ***

        Object.define(window, 'App', {get: console.log.bind(null, 'World') });

        // *** I can only modify codes within this block ***

      }

      function b() {

        'use strict';

        App();

      }

      a();

      b();

    };

    sandbox(App, ()=>({}), undefined);