Javascript 如何在 ng-if 和变量中使用过滤器？
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How to use filter in ng-if and variable?
提问by Edward Tanguay
In this example, I use filter in the ng-repeat, but how do I use it in a variable and ng-if, something like:
在这个例子中，我在 中使用过滤器ng-repeat，但是我如何在变量和中使用它ng-if，例如：
{{languages.length | filter: {available: true}}}
and
和
ng-if="languages.length == 0 | filter: {available: true}"
See Fiddle.
见小提琴。
HTML
HTML
<div ng-controller="mainController">
<div>There are {{languages.length}} languages in total.</div>
<div>??? There are {{languages.length}} languages available.</div>
<div ng-if="languages.length == 0">??? Sorry, there are no languages available.</div>
<ol>
<li ng-repeat="language in languages | filter: {available: true}">{{language.name}}</li>
</ol>
</div>
AngularJS
AngularJS
$scope.languages = [
{id:1, name:"German", available: false},
{id:2, name:"English", available: true},
{id:3, name:"French", available: false},
{id:4, name:"Italian", available: true},
{id:5, name:"Spanish", available: false}
];
回答by Mistalis
Can you try this?
你能试试这个吗？
<div ng-controller="mainController">
<div>There are {{languages.length}} languages in total.</div>
<div>There are {{(languages|filter:{available:true}).length}} languages available.</div>
<div ng-if="(languages|filter:{available:true}).length == 0">Sorry, there are no languages available.</div>
<ol>
<li ng-repeat="language in languages | filter: {available: true}">{{language.name}}</li>
</ol>
</div>
回答by Dmitri Algazin
Just to update previous answer, no need to filter three times, create new variable 'filtered' on first filter:
只是为了更新以前的答案，不需要过滤三次，在第一个过滤器上创建新变量“过滤”：
<div ng-controller="mainController">
<div>There are {{languages.length}} languages in total.</div>
<div>There are {{(filtered = (languages|filter:{available:true})).length}} languages available.</div>
<div ng-if="filtered.length == 0">Sorry, there are no languages available.</div>
<ol>
<li ng-repeat="language in filtered">{{language.name}}</li>
</ol>
filtered=[{{filtered}}]
</div>
回答by SSD
<div ng-if="(answerText|lowercase)=='true'">T</div>
<div ng-if="(answerText|lowercase)=='false'">F</div>
<div ng-if="(answerText|lowercase)=='false'">F</div>
This works for me
这对我有用
