错误：过滤器：使用Lodash Groupby过滤器时的notarray

Question

这就是我上市的方式。

result = (input + pad).substring(0, pad.length());
results: "******" | "abcd**" | "abcdef"

我有另一个功能，我想用于过滤器：它看起来像下面。

    $scope.events = [];
    $scope.groupevent = [];

    Event.getList().then(function(data){
        $scope.events = data.events;
        $rootScope.events = data.events;

        angular.forEach($scope.events,function(value,key){
            value.groupdate = value.startDate.substring(0,7)+'-01';
            console.log(value.groupdate);
        });

        $scope.events = _.orderBy($scope.events, ['startDate'], ['asc']);
        $scope.groupevent = _.groupBy($scope.events,'groupdate');
        console.log($scope.groupevent);
    });

但是当我$scope.greaterThan = function(){ var prop='endDate'; var val=Date.now(); return function(item){ return new Date(item[prop]) > val; } }; 时：

ng-repeat

它说：ng-repeat="(key,x) in groupevent | filter:greaterThan()"