javascript - Javascript对象和继承的首次尝试: is it correct

Question

我正在尝试学习如何在 Javascript 中创建类以及如何执行对象继承。我已经遵循了一些教程，但我不确定我的代码是否正确。

• 我是否正确创建了公共(public)函数和属性？如果不是，我应该改变什么？
• 我是否正确创建了特权函数和属性？如果不是，我应该改变什么？
• 我是否正确创建了私有(private)函数和属性？如果不是，我应该改变什么？
• 我是否正确地重写了函数？
• 我是否正确执行继承？
• 如果有什么问题，你能告诉我代码应该是什么样子吗？

这是我创建基类然后创建子类的简单代码:

/* Base Object Class */
function BaseClass( /*string*/ objType )
{
   /* Public: */
   this.name = "blah";

   BaseClass.prototype.getName = function()
   {
    return this.name;
   }

   BaseClass.prototype.setName = function( newName )
   {
      var oldName = this.name;
      this.name   = newName;

      return oldName;
   }


   /* Private: */
   var attributeMap = {};

   this.constructor = function()
   {
      // this objects default constructor. Is this correct?
      attributeMap["type"]     = objType;
      attributeMap["uniqueID"] = "Base"+(++INSTANCE_COUNT);
   }


   /* Privileged: */
   // Will an object that inherits from this class be able to override the following functions? 
   // Or do I have to make these functions public in order to override them?
   this.toString = function()
   {
      var s = "";
      for (var attrib in attributeMap)
      {
         s += attrib + ": " + attributeMap[attrib] + ", ";
      }
      return s;
   }

   this.getType = function()
   {
      return attributeMap["type"];
   }

   this.renderObject = function()
   {
      // TODO: render object on HTML5 canvas
   }

   this.parseXMLNode = function( /*XML Node*/ nodeXML, /*string*/ objType )
   {
      var attribs = nodeXML.attributes;

      for (var i=0; i<attribs.length; i++)
      {
         attributeMap[ attribs[i].nodeName ] = attribs[i].nodeValue;
      }

      // store children 
      if ( nodeXML.hasChildNodes() )
      {
         attributeMap["children"] = nodeXML.childNodes;
      }

      reformatObjectInnerHTML();
   }

}


// Static Variables //
BaseObject.INSTANCE_COUNT = 0;


// My Child Class //
ChildClass.prototype = new BaseObject( objType );     // make ChildClass inherit from BaseClass
ChildClass.prototype.constructor = function(ObjType)  // Make the ChildClass call the BaseClass constructor
{
   BaseObject.prototype.constructor.call(this, objType);
}

function ChildClass( /*string*/ objType )
{
   /* Privileged: */
   // Attempt to override BaseClass function renderObject()
   this.renderObject = function()
   {
       alert("ChildClass::renderObject();");
       // Does this override the BaseClass renderObject() function?
   }
}

Answer 1

How to Achieve Private, Public, Privileged members in Javascript

尽管我不建议您编写这样的代码。 JavaScript 与 C++ 不同。不要在 JavaScript 中编写 C++ 代码。