如何使用任意原型创建一个可调用的JS对象？ [英] How do I make a callable JS object with an arbitrary prototype?

问题描述

可能重复：

一个JavaScript对象是否可以有一个原型链，但也可以是一个函数？

< blockquote>

我正在寻找一个带有任意原型链的可调用JavaScript对象，但没有修改Function.prototype。

换句话说，这是必须的：

  var o = {x：5 }; 
 var foo = bar（o）; 
 assert（foo（）===Hello World！）; 
删除foo.x; 
 assert（foo.x === 5）; 
  

不进行全局更改

解决方案

没有什么能够阻止你将任意属性添加到函数中，例如：

 函数bar（o）{
 var f = function（）{returnHello World！; } 
 o .__ proto__ = f .__ proto__; 
 f .__ proto__ = o; 
返回f; 
} 
 
 var o = {x：5}; 
 var foo = bar（o）; 
 assert（foo（）===Hello World！）; 
删除foo.x; 
 assert（foo.x === 5）; 
  

我相信应该做你想做的。

这是通过将对象 o 注入到原型链中来实现的，但需要注意以下几点：

• 我不知道IE是否支持 __ proto __ ，或者甚至有一个等价的，frome一些评论，看起来只适用于firefox和safari （如camino，chrome等）也是如此。
只有真正必要的

• o .__ proto__ = f .__ proto __; 对于像function.toString这样的函数原型函数，您可能只想跳过它，特别是如果您期望 o 具有有意义的原型。

Possible Duplicate:
Can a JavaScript object have a prototype chain, but also be a function?

I'm looking to make a callable JavaScript object, with an arbitrary prototype chain, but without modifying Function.prototype.

In other words, this has to work:

var o = { x: 5 };
var foo = bar(o);
assert(foo() === "Hello World!");
delete foo.x;
assert(foo.x === 5);

Without making any globally changes.

解决方案

There's nothing to stop you from adding arbitrary properties to a function, eg.

function bar(o) {
    var f = function() { return "Hello World!"; }
    o.__proto__ = f.__proto__;
    f.__proto__ = o;
    return f;
}

var o = { x: 5 };
var foo = bar(o);
assert(foo() === "Hello World!");
delete foo.x;
assert(foo.x === 5);

I believe that should do what you want.

This works by injecting the object o into the prototype chain, however there are a few things to note:

• I don't know if IE supports __proto__, or even has an equivalent, frome some's comments this looks to only work in firefox and safari based browsers (so camino, chrome, etc work as well).
• o.__proto__ = f.__proto__; is only really necessary for function prototype functions like function.toString, so you might want to just skip it, especially if you expect o to have a meaningful prototype.

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