ng-repeat过滤器空值不显示 [英] ng-repeat filter null value not displaying

问题描述

pre $ c $ ng $ repeat =p in foo | filter：filter2

其中filter2是

<$ （p）{
如果（p.state === null）{
return p.state;
} else {
return;
}
};

这里是我正在说的一个plnkr： http://plnkr.co/edit/cj3v1fuBu6sHVI7A4qlq?p=preview

过滤器的工作原理是什么，但一个空，但我只想空显示。我可以尝试将所有空值更改为默认值字符串以外的空值？是否有任何地方可以让过滤器使用空值？

解决方案

我认为唯一错误的是您需要返回整个对象。

基于Brad的评论，我去检查了文档，他是对的。我的代码示例工作的唯一原因是它返回了一个'​​truthy'值。

我修改了下面的代码示例，将其考虑在内。

以下是过滤器：

$ $ $ $ $ $ $ $ $ scope.filter2 = function（p）{
if（p.state === null）{
return true;
} else {
return;
}
};

以下是文档中的相关部分：

函数（actual，expected）：该函数将被赋予对象值和谓词值进行比较，如果该项目应包含在过滤结果中，则返回true。 b $ b

plunkr

Why won't angular display values that are null when I apply:

ng-repeat="p in foo | filter: filter2"

where filter2 is

 $scope.filter2 = function(p){
    if (p.state === null){
        return p.state;
    } else{
        return;
    }
};

here's a plnkr with what I'm saying: http://plnkr.co/edit/cj3v1fuBu6sHVI7A4qlq?p=preview

The filter works when it's anything but a null but I'm trying to only the null ones to display. I could try changing all the null values to a default value string other than a null? Is there anywhere to get the filter to work with nulls?

解决方案

I think the only thing wrong was that you needed to return the entire object.

Based on Brad's comment below, I went and checked the docs and he's right. The only reason my code sample works is because it's returning a 'truthy' value.

I've modified my code example below to take that into account.

Here's the filter:

$scope.filter2 = function(p){
    if (p.state === null){
        return true;
    } else{
        return;
    }
};

Here is the relevant section in the docs:

function(actual, expected): The function will be given the object value and the predicate value to compare and should return true if the item should be included in filtered result.

plunkr

这篇关于ng-repeat过滤器空值不显示的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！