function filterFilter() {
  return function(array, expression, comperator) {
    if (!isArray(array)) return array;
    var predicates = [];
    predicates.check = function(value) {
      for (var j = 0; j < predicates.length; j++) {
        if(!predicates[j](value)) {
          return false;
        }
      }
      return true;
    };
    switch(typeof comperator) {
      case "function":
        break;
      case "boolean":
        if(comperator == true) {
          comperator = function(obj, text) {
            return angular.equals(obj, text);
          }
          break;
        }
      default:
        comperator = function(obj, text) {
          text = (''+text).toLowerCase();
          return (''+obj).toLowerCase().indexOf(text) > -1;
        };
    }
    var search = function(obj, text){
      if (typeof text == 'string' && text.charAt(0) === '!') {
        return !search(obj, text.substr(1));
      }
      switch (typeof obj) {
        case "boolean":
        case "number":
        case "string":
          return comperator(obj, text);
        case "object":
          switch (typeof text) {
            case "object":
              return comperator(obj, text);
              break;
            default:
              for ( var objKey in obj) {
                if (objKey.charAt(0) !== '$' && search(obj[objKey], text)) {
                  return true;
                }
              }
              break;
          }
          return false;
        case "array":
          for ( var i = 0; i < obj.length; i++) {
            if (search(obj[i], text)) {
              return true;
            }
          }
          return false;
        default:
          return false;
      }
    };
    switch (typeof expression) {
      case "boolean":
      case "number":
      case "string":
        expression = {$:expression};
      case "object":
        for (var key in expression) {
          if (key == '$') {
            (function() {
              if (!expression[key]) return;
              var path = key
              predicates.push(function(value) {
                return search(value, expression[path]);
              });
            })();
          } else {
            (function() {
              if (typeof(expression[key]) == 'undefined') { return; }
              var path = key;
              predicates.push(function(value) {
                return search(getter(value,path), expression[path]);
              });
            })();
          }
        }
        break;
      case 'function':
        predicates.push(expression);
        break;
      default:
        return array;
    }
    var filtered = [];
    for ( var j = 0; j < array.length; j++) {
      var value = array[j];
      if (predicates.check(value)) {
        filtered.push(value);
      }
    }
    return filtered;
  }
}
@ngdoc filter
@name ng.filter:filter
@function

@description
Selects a subset of items from `array` and returns it as a new array.

Note: This function is used to augment the `Array` type in Angular expressions. See
{@link ng.$filter} for more information about Angular arrays.

@param {Array} array The source array.
@param {string|Object|function()} expression The predicate to be used for selecting items from
  `array`.

  Can be one of:

  - `string`: Predicate that results in a substring match using the value of `expression`
    string. All strings or objects with string properties in `array` that contain this string
    will be returned. The predicate can be negated by prefixing the string with `!`.

  - `Object`: A pattern object can be used to filter specific properties on objects contained
    by `array`. For example `{name:"M", phone:"1"}` predicate will return an array of items
    which have property `name` containing "M" and property `phone` containing "1". A special
    property name `$` can be used (as in `{$:"text"}`) to accept a match against any
    property of the object. That's equivalent to the simple substring match with a `string`
    as described above.

  - `function`: A predicate function can be used to write arbitrary filters. The function is
    called for each element of `array`. The final result is an array of those elements that
    the predicate returned true for.

@param {function(expected, actual)|true|undefined} comparator Comparator which is used in
    determining if the expected value (from the filter expression) and actual value (from
    the object in the array) should be considered a match.

  Can be one of:

    - `function(expected, actual)`:
      The function will be given the object value and the predicate value to compare and
      should return true if the item should be included in filtered result.

    - `true`: A shorthand for `function(expected, actual) { return angular.equals(expected, actual)}`.
      this is essentially strict comparison of expected and actual.

    - `false|undefined`: A short hand for a function which will look for a substring match in case
      insensitive way.

@example
   <doc:example>
     <doc:source>
       <div ng-init="friends = [{name:'John', phone:'555-1276'},
                                {name:'Mary', phone:'800-BIG-MARY'},
                                {name:'Mike', phone:'555-4321'},
                                {name:'Adam', phone:'555-5678'},
                                {name:'Julie', phone:'555-8765'},
                                {name:'Juliette', phone:'555-5678'}]"></div>

       Search: <input ng-model="searchText">
       <table id="searchTextResults">
         <tr><th>Name</th><th>Phone</th></tr>
         <tr ng-repeat="friend in friends | filter:searchText">
           <td>{{friend.name}}</td>
           <td>{{friend.phone}}</td>
         </tr>
       </table>
       <hr>
       Any: <input ng-model="search.$"> <br>
       Name only <input ng-model="search.name"><br>
       Phone only <input ng-model="search.phone"><br>
       Equality <input type="checkbox" ng-model="strict"><br>
       <table id="searchObjResults">
         <tr><th>Name</th><th>Phone</th></tr>
         <tr ng-repeat="friend in friends | filter:search:strict">
           <td>{{friend.name}}</td>
           <td>{{friend.phone}}</td>
         </tr>
       </table>
     </doc:source>
     <doc:scenario>
       it('should search across all fields when filtering with a string', function() {
         input('searchText').enter('m');
         expect(repeater('#searchTextResults tr', 'friend in friends').column('friend.name')).
           toEqual(['Mary', 'Mike', 'Adam']);

         input('searchText').enter('76');
         expect(repeater('#searchTextResults tr', 'friend in friends').column('friend.name')).
           toEqual(['John', 'Julie']);
       });

       it('should search in specific fields when filtering with a predicate object', function() {
         input('search.$').enter('i');
         expect(repeater('#searchObjResults tr', 'friend in friends').column('friend.name')).
           toEqual(['Mary', 'Mike', 'Julie', 'Juliette']);
       });
       it('should use a equal comparison when comparator is true', function() {
         input('search.name').enter('Julie');
         input('strict').check();
         expect(repeater('#searchObjResults tr', 'friend in friends').column('friend.name')).
           toEqual(['Julie']);
       });
     </doc:scenario>
   </doc:example>