var undefined = void 0;与jquery的关闭vs…?

Reading underscore's source, I noticed the use of void 0 instead of undefined. I know in some browsers undefined can be overwritten, and that a solution to this, in many cases, is just omitting an argument when calling a function, or return;-ing. In fact, for minification purposes, it makes much more sense to do this rather than using void 0.

在阅读下划线的源代码时，我注意到void 0而不是undefined。我知道在某些浏览器中没有定义可以被覆盖，而且在很多情况下，解决这个问题的方法就是在调用函数或返回时省略一个参数。事实上，为了缩小规模，这样做更有意义，而不是使用void 0。

Also, jquery's aproach to this issue:

此外，jquery对这个问题的建议是:

(function (window, undefined){
  /* ... */
}(window));

seems to be better in every sense. It is much more readable than void 0, can be minified further, and might give some tiny performance boost as explained in the linked answer.

似乎在各个方面都更好。它比void 0可读性强得多，可以进一步缩小，并且可以提供一些小的性能提升，如链接答案中所解释的那样。

OK, void 0 appears about 6 times in underscore and 9 in backbone, so it doesn't make much of a difference. So, my question is: Is there any reason or corner cases where void 0 is preferable?

void 0在下划线中出现了大约6次，在主干中出现了9次，所以没有多大区别。所以，我的问题是:是否有任何理由或角落的情况下，void 0是更可取的?

2 个解决方案

#1

Here's an example of why the "undefined argument" thing can be a horrible idea.

这里有一个例子，解释为什么“未定义的论点”是一个可怕的想法。

Let's say you get used to doing it. And you start applying it to other functions too, like this:

假设你习惯了。你也可以把它应用到其他函数中，比如:

function doSomething(undefined) {
    // blah blah blah
    if( something == undefined) {
        // problem
    }
}

All good, right?

一切美好的,对吧?

Let's say that this function is an event handler.

假设这个函数是一个事件处理程序。

someElement.onclick = doSomething;

Oh dear. doSomething gets passed an Event object, which is most certainly not undefined!

哦亲爱的。doSomething获得一个事件对象，这个对象肯定不是没有定义的!

void 0 is much more robust, as it doesn't rely on a quirk or an assumption to work.

void 0要健壮得多，因为它不依赖于一个怪癖或假设来工作。

#2

As you said, void 0 means undefined. Since older browsers undefined can be overwritten. void 0 is guaranteed and will always be undefined. But i do not think, there is no much difference between no argument undefined(jquery way) and void 0.

正如你所说，void 0表示没有定义。由于未定义的旧浏览器可以被覆盖。void 0是有保证的，并且总是没有定义的。但是我认为，在没有未定义的参数(jquery方式)和void 0之间没有什么区别。

I think, void 0 is just a coding preference.

我认为，void 0只是一个编码偏好。

#1