javascript 函数是对象吗? [英] javascript functions are objects?

问题描述

我在 Javascript 问题上苦苦挣扎了一段时间，但我无法在网上找到解释.我想这是因为我没有输入正确的关键字，这也可能与我为什么为此苦苦挣扎有关.

I am struggling with a Javascript question for some time now and I was not able to find an explanation on the web. I guess it is because I do not enter the right keywords which might also be related to why I am struggling with this at all.

我的基本假设是可以更改对象:

My basic assumption is that it is possible to alter objects:

> var x = {'n': 2};
> x['n']
2
> x['n'] = 3;
3

哇哦，那行得通.但仍然(函数也是对象):

pheww that worked. But still (functions are objects, too):

> var addn = function(a) {
    var n = 2;
    return n + a;
}

> addn(3);
5
> addn['n'] = 3;
3
> addn(3);
5

这次我没能改变'n'.有没有办法在保持功能风味的同时解决这个问题?与完全面向对象相反.我有一个相关的问题是如何维护函数的依赖关系，例如为了测试 - 再次不去面向对象?当然，我正在寻找解决方案，但如果可能的话，我也想了解 Javascript 中的哪种机制让我陷入困境.

This time I was not able to change 'n'. Is there a way to fix this while keeping the functional flavor? As opposed to going fully OO. A related question I have would be how to maintain dependencies of functions for the purpose of for example testing - again w/o going OO? Of cause I am looking for a solution but if possible I would also like to understand which mechanism in Javascript makes me struggling.

干杯，

标记

免责声明:通过提及 OO，我无意反对 OO.我也无意反对 VI 或 Emacs.如果我以某种方式伤害了您的感情，请跳过这一点.

Disclaimer: By mentioning OO I do not intent to say anything against OO. And I do not intent to say anything against VI or Emacs either. If I somehow hurt your feelings please skip this one.

推荐答案

如果我正确理解您的问题，您可以为匿名函数命名并通过该名称访问函数对象的属性:

If I understand your question correctly, you can give a name to your anonymous function and access the function object's properties through that:

var addn = function func(a) {
  return func.n + a;
};

addn['n'] = 3;
addn(3); // returns 6

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