角度ng重复指数

Question

我正在使用Angular ng-repeat，如下所示：

<ul>
  <li ng-repeat="tab in tabs" ng-class="{ active:isSet($index) }" ng-click="setTab($index, tab)">&nbsp;{{tab}}&nbsp;</li>
</ul>

但最终的HTML是这样的：

<ul>
  <li ng-repeat="tab in tabs" ng-class="{ active:isSet($index) }" ng-click="setTab($index, tab)" class="ng-scope ng-binding">&nbsp;First item&nbsp;</li>
  <li ng-repeat="tab in tabs" ng-class="{ active:isSet($index) }" ng-click="setTab($index, tab)" class="ng-scope ng-binding">&nbsp;Second item&nbsp;</li>
</ul>

Wheras我希望正确呈现$ index，如下所示：

<ul>
  <li ng-repeat="tab in tabs" ng-class="{ active:isSet(0) }" ng-click="setTab(0, tab)" class="ng-scope ng-binding">&nbsp;First item&nbsp;</li>
  <li ng-repeat="tab in tabs" ng-class="{ active:isSet(1) }" ng-click="setTab(1, tab)" class="ng-scope ng-binding">&nbsp;Second item&nbsp;</li>
</ul>

我做错了什么？