如何确定函数是否为空 [英] How to determine if a function is empty

问题描述

我希望能够检查给定的功能是否为空。也就是说，它的主体没有任何东西，例如：

I want to be able to check whether a given function is empty or not. That is, there is nothing in its body, eg:

function foo() {}
function iAmEmpty(a) {
    // yep, empty
}

随着一些初步的游戏，我有一些我认为可能没问题的东西，使用 toString（）和一些正则表达式。

With some initial playing around, I've got something which I think might be ok, by using toString() and some regexes.

function foo(a, b, c) {}

/^function[^{]+\{\s*\}/m.test(foo.toString());  // true

function bar(a, b, c) { var d; }

/^function[^{]+\{\s*\}/m.test(bar.toString());  // false

我只是想知道是否有更好的方法？您可以看到以上问题吗？

I was just wondering if there was a better approach? Are there any problems with the above you can see?

推荐答案

这是不可取的。没有标准确切地确定函数的 toString（）方法应该返回什么，所以即使你在当前的浏览器中使用它，未来的浏览器也可以合理地改变它们的实现并打破你的代码。

This isn't advisable. There is no standard determining precisely what a function's toString() method should return, so even if you get this working in current browsers, future browsers may justifiably change their implementation and break your code.

Kangax简要介绍了这一点： http://perfectionkills.com/those-tricky-functions/

Kangax has written briefly about this: http://perfectionkills.com/those-tricky-functions/

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