text: const privates = new WeakMap();
  
  function Public() {
    const me = {
      // Private data goes here
      name:"张三"
    };
    privates.set(this, me);
  }
  
  Public.prototype.sayHi = function () {
    const me = privates.get(this);
    // Do stuff with private data in `me`...
    console.log(me.name)
  };
  
  
  var pub = new Public()
  pub.sayHi()