是否有`orderBy`过滤器功能，它允许它正确处理可选属性？(Is there `orderBy` filter feature that allows it to handle optional properties correctly?)

 是否有一种简单，优雅的方式来按顺序排序数组，但将任何缺失值视为0 （或任意设置值）而不是undefined ？ 
 
 例如，以下代码 
 
<li ng-repeat="item in items | orderBy:['-optionalKey', 'secondaryKey']">{{ item.secondaryKey }}</li>
 
 用数据集 
 
$scope.items = [
    {secondaryKey: 75, optionalKey: 25},
    {secondaryKey: 100},
    {secondaryKey: 50, optionalKey: 0},
];
 
 会产生这个 
 
<li>75</li>
<li>50</li>
<li>100</li>
 
 而不是这个 
 
<li>100</li>
<li>75</li>
<li>50</li>
 
 ？ 
 
 在这里玩它： http ： //plnkr.co/edit/G3nQyEzHfUiiovJTD44Y？p = preview 
 
 我意识到我可以重新实现整个orderBy过滤器，但这不是很orderBy维护或面向未来。 我还可以在常规orderBy过滤器中使用函数作为谓词，但是我仍然需要重新实现已经内置到orderBy的复杂参数处理（例如深度键嵌套， + / -反转等）。 我真正想知道的是，如果有一些我不知道的语法可以让我做这样的事情： 
 
<li ng-repeat="item in items | orderBy:['-optionalKey', 'secondaryKey']:false:0">{{ item.secondaryKey }}</li>
 
 ...其中第三个参数（ 0 ）表示我想要将falsy / missing键视为的值。 

Is there a simple, elegant way to order an array as per usual but treat any missing values as 0 (or any arbitrarily set value) instead of undefined?
 
e.g. so that the following code
 
<li ng-repeat="item in items | orderBy:['-optionalKey', 'secondaryKey']">{{ item.secondaryKey }}</li>
 
with a dataset like
 
$scope.items = [
    {secondaryKey: 75, optionalKey: 25},
    {secondaryKey: 100},
    {secondaryKey: 50, optionalKey: 0},
];
 
would produce this
 
<li>75</li>
<li>50</li>
<li>100</li>
 
instead of this
 
<li>100</li>
<li>75</li>
<li>50</li>
 
?
 
Play with it here: http://plnkr.co/edit/G3nQyEzHfUiiovJTD44Y?p=preview
 
I realize I could reimplement the entire orderBy filter, but that's not very maintainable or future-proof. I could also use a function as a predicate inside the regular orderBy filter, but then I would still have to reimplement the complex arguments handling that's already built-in to orderBy (e.g. deep key nesting, +/- reversing, etc.). What I'm really wondering is if there's some syntax I'm not aware of that would allow me to do something like this:
 
<li ng-repeat="item in items | orderBy:['-optionalKey', 'secondaryKey']:false:0">{{ item.secondaryKey }}</li>
 
…where the third argument (0) represents the value I want to treat falsy/missing keys as.

原文：https://stackoverflow.com/questions/27117227