如何知道何时由于过滤器而无法显示结果?
<input type="text" class="form-control" ng-model="search" placeholder="Search...">
<div ng-show="contents.length !== 0">
<h2>Contents</h2>
<div class="panel panel-default" ng-repeat="content in contents | filter:search">
<div class="panel-heading">
<h3 class="panel-title">{{content.title}}</h3>
</div>
<div class="panel-body">{{content.description}}</div>
</div>
</div>