如何在ng-if和变量中使用过滤器？

在此示例中，我在中使用过滤器ng-repeat，但是如何在和中使用它ng-if，例如：

{{languages.length | filter: {available: true}}}

和

ng-if="languages.length == 0 | filter: {available: true}"

参见小提琴。

的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

$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}
];