How to call any function as a $filter in AngularJs

Recently I had this little trouble. I had a simple angular controller, which filtered some array of items. I did not want to define the filter in a “global space” because I knew it will be used only by this one controller. So this first thing was to define the custom filter function. Like this

$scope.customFilter = (item)=> {
  return item.someProperty == $scope.filterValue;
};

Then call in UI like this.

<htmlElement ng-repeat="item in itemList | filter:customFilter"></htmlElement>

So far nothing special, just what is in the angular documentation. But I needed to call that custom filter again, but not from UI but programaticaly. The way how to invoke custom filter without registering the function via myAngularModule.filter(‘customFilter’, function() {…}) is this.

var filteredItems = $filter('filter')($scope.itemList, $scope.customFilter)