不要JavaScript数组和对象有一组订单？ [英] Do javascript arrays and objects have a set order?

问题描述

这问题是我的创建涉及从JSON对象HTML表格当前的项目之一是至关重要的。我想我可以创造条件，使他们为HTML之前我的数组/对象进行排序的功能。我唯一​​担心的是，为了不JavaScript的事，如果我是创建一个新的阵列使用相同的数据（以不同的顺序）作为另一个阵列他们最终会是相同的。

This question is vital to one of my current projects involving creating HTML tables from JSON objects. I was thinking I could create functions that would sort my Arrays/Objects before rendering them as HTML. My only concern is that order doesn't matter in JavaScript, and if I were to create a new Array with the same data (in a different order) as another Array they would end up identical.

我想不出一个快速的方法来测试这一点，所以我问在这里。

I can't think of a fast way to test this, so I'm asking here.

推荐答案

其他回答阵列上，所以我只是想提供对象的某些信息。

Others have answered on arrays, so I just wanted to provide some info on objects.

在说，这个标准是不存在的，但它的实际的定义是，一个对象将插入顺序列举，所不同的是数字按升序排列并首先列举。我说一般，但这种行为是隔靴搔痒标准（也没有像jQuery框架规范它，据我所知）。

On that, the standard is non-existent, but it's de facto definition is that an object will enumerate in insertion order, with the exception that numbers are placed in ascending order and enumerated first. I say typically, but this behavior is nowhere near standardized (nor do frameworks like jQuery standardize it, AFAIK).

您可以测试使用该浏览器的jsfiddle：

You can test browsers using this jsFiddle:

http://jsfiddle.net/7cCpu/4/

对象 {富：酒吧，吧：富，巴兹：巴兹，3：3，2：2，1 ：1} 列举如下：

foo, bar, baz, 3, 2, 1 // insertion order

1, 2, 3, foo, bar, baz // Chrome enumeration
1, 2, 3, foo, bar, baz // Opera
1, 2, 3, foo, bar, baz // IE9
foo, bar, baz, 3, 2, 1 // Firefox (!!!)

我没有安装Safari浏览器，但我的假设的是一样的Chrome。在任何情况下，关键是你的可以的做出假设 - 它不是随机的 - 但它可能是一个更好的主意，如果你依赖于准确的枚举使用数组

I don't have Safari installed, but I assume it's the same as Chrome. In any case, the point is that you can make assumptions -- it's not random -- but it's probably a better idea to use an array if you depend on exact enumeration.

均匀厉害是杜里指出以上，其中删除和替换的关键变造的事情进一步的价值。看的时候我会发生什么吧删除做 Object.bar =富然后枚举：

Even nastier is what duri pointed out above, where deleting and replacing the value for a key alters things further. Watch what happens when I delete bar and do Object.bar = "foo" then enumerate:

1, 2, 3, foo, baz, bar // Chrome enumeration
1, 2, 3, foo, baz, bar // Opera
1, 2, 3, foo, bar, baz // IE9 (!!!)
foo, baz, 3, 2, 1, bar // Firefox (!!!)

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