Question

是否可以动态附加到对象实例的原型？例如，我有两个dell对象，一个是笔记本电脑，另一个是桌面。我希望能够创建两个dell实例，然后将原型扩展到笔记本电脑或台式机，这样我就可以使用适当的getter / setter。

JSFiddle链接： http://jsfiddle.net/QqXgV/1/

var dell = function(){}
dell.prototype = new computer();
dell.prototype.constructor = dell;

var hp = function(){}
hp.prototype = new computer();
hp.prototype.constructor = hp;

var computer = function(){}
computer.prototype.setType = function(type){
  //Here is where I would extend.
  this.prototype extends window[type].prototype;
}

var laptop = function(){}
laptop.prototype.getKeyboard = function(){
  return "motherboard";
}

var desktop = function(){}
desktop.prototype.getKeyboard = function(){
  return "usb";
}

var dellDesktop = new dell();
dellDesktop.setType("desktop");

var dellLaptop = new dell();
dellLaptop.setType("laptop");

//This is the end goal.
dellDesktop.getKeyboard(); //Returns usb
dellLaptop.getKeyboard(); //Returns motherboard
//And then be able to do the same thing with hp.

Answer 1

如果戴尔可以是笔记本电脑或台式机，则可以创建DellLaptop和DellDesktop构造函数。但笔记本电脑配备超极本和上网本，因此必须创建DellLaptopUltrabook和DellLaptopNetBook。因此，如果某些东西可以是这个或那个，而其他对象可以是这个或那个（如HP也可以是笔记本电脑或桌面），也许以下模式可以提供帮助：

var Computer = function(){};
//proxy getKeyboard based on what type it is
Computer.prototype.getKeyboard = function(){
  return this.type.getKeyboard.call(this);
};

var Dell = function(args){
  //do some checks on args here
  //re use Computer constructor
  Computer.call(this.args);
  //re use laptop or Desktop constructor code
  args.type.call(this,args);
  //re use Laptop or Desktop protype members
  this.type=args.type.prototype;

};
Dell.prototype = Object.create(Computer.prototype);
Dell.prototype.constructor = Dell;

var Laptop = function(){};
Laptop.prototype.getKeyboard = function(){
  return "motherboard";
};
//ultrabook and netbook can inherit from Laptop
//  so you could pass UltraBook or Netbook as type


var Desktop = function(){};
Desktop.prototype.getKeyboard = function(){
  return "usb";
};

var dellDesktop = new Dell({type:Desktop});

var dellLaptop = new Dell({type:Laptop});

//This is the end goal.
console.log(dellDesktop.getKeyboard()); //Returns usb
console.log(dellLaptop.getKeyboard()); //Returns motherboard

例如，在JavaScript中动态更改原型

1 个答案: