如何在JavaScript中对NodeList进行重新排序/排序? [英] How can I reorder/sort a NodeList in JavaScript?

问题描述

我有一个我认为应该是一个简单的问题；让我快速解释一下:

I have what I think should be a straightforward question; let me quickly explain:

在我的JavaScript中，food.xml的读取方式为:

In my JavaScript, food.xml is read in with:

getMenuXml.open("GET","food.xml",false);
getMenuXml.send();
xmlDoc=getMenuXml.responseXML;
xmlFoodList = xmlDoc.getElementsByTagName("food");

所以现在我有了一个包含所有食物元素的NodeList xmlFoodList.到目前为止很好.问题是我想根据内部的元素<category>对节点进行排序.我可以这样阅读:

so that now I have a NodeList xmlFoodList with all the food elements. Great so far. The problem is I want to sort the nodes based on an element <category> inside. I can read that with:

xmlFoodList[i].getElementsByTagName("category")[0].childNodes[0].nodeValue

稍后在我的代码中，食物项将显示在列表中，并且正如您期望的那样，我希望将同一类别的食物一起列出.因此，我的问题是:如何根据类别对xmlFoodList中的节点重新排序?

Later in my code, the food items are displayed in a list, and as you'd expect, I want food of the same category to be listed together. So, my question is: How can I reorder the nodes in xmlFoodList based on their category?

注意:我无法更改传入的food.xml，并且由于列表已填充，我不想编辑以后的代码来进行排序.我不想将NodeList转换为数组，因为我不得不重写很多以后的代码.性能实际上并没有太大的关系，因此可以随意克隆/嵌套所有所需的循环.谢谢您的宝贵时间.

Notes: I can't change food.xml coming in, and I don't want to edit my later code to do the sorting as the list is populated. I don't want to convert the NodeList to an array, since I'd have to rewrite a lot of later code. Performance isn't actually much of a concern, so feel free to clone/nested loop all you want. Thanks for your time.

推荐答案

如果首先将它们转换为数组，则可以对NodeList的元素进行排序:

You can order the elements of the NodeList, if you convert them to an array first:

var foods = xmlDoc.getElementsByTagName("food");
var foodsArray = Array.prototype.slice.call(foods, 0);

然后您可以使用sort方法:

foodsArray.sort(function(a,b) {
    var aCat = a.getElementsByTagName("category")[0].childNodes[0].nodeValue;
    var bCat = b.getElementsByTagName("category")[0].childNodes[0].nodeValue;
    if (aCat > bCat) return 1;
    if (aCat < bCat) return -1;
    return 0;
});

但是，这在很大程度上取决于您的XML模式-例如，如果您的食物属于多个类别，那么它们只能按上述代码中的第一个类别进行排序.

This is highly dependent on your XML schema though - if, for example, you had foods which were in more than one category they would only be sorted by the first category in the code above.

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