javascript - AngularJS - 使用过滤器和 groupBy 后计算结果

Question

我正在使用 Angular 和 angular-filter

过滤和分组正在运行。但我也想检查过滤列表是否为空，类似于这个问题: AngularJS - placeholder for empty result from filter

在下面的示例中，我使用 player in FilteredPlayers = (players | filter:search) 通过 filteredPlayers.length 访问计数

如何对示例中的分组列表执行类似的操作？

代码:

var app = angular.module('myApp', ['angular.filter']);
app.controller('myCtrl', ['$scope', function($scope) {
  $scope.players = [
  {name: 'Gene', team: 'alpha'},
  {name: 'George', team: 'beta'},
  {name: 'Steve', team: 'gamma'},
  {name: 'Paula', team: 'beta'},
  {name: 'Scruath', team: 'gamma'}
];
}]);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-filter/0.5.8/angular-filter.js"></script>

<div ng-app="myApp">
  <div ng-controller="myCtrl">
    <input type="text" ng-model="search">
    <hr>
    <div ng-hide="filteredPlayers.length">
      This list is empty. (this is working).
    </div>
    <ul>
      <li ng-repeat="player in filteredPlayers = (players | filter:search)">
        player: {{ player.name }}
      </li>
    </ul>
    <hr>
    <div>
      The list is empty. (this is not working - always displayed).
    </div>
    <ul ng-repeat="(key, value) in players | filter:search | groupBy: 'team'">
      Group name: {{ key }}
      <li ng-repeat="player in value">
        player: {{ player.name }}
      </li>
    </ul>
  </div>
</div>

Answer 1

你可以做类似的事情:

<ul ng-repeat="(key, value) in (filteredPlayers = (players | filter:search) | groupBy: 'team')">
    ..
</ul>

<h1>Length: {{ filteredPlayers.length }}</h1>