don't replace false keys

Author: AlexCuse

src/_filter/collection/group-by.js

@@ -17,7 +17,7 @@ angular.module('a8m.group-by', [ 'a8m.filter-watcher' ])
         getParse = $parse(property),
         get = function(el) {
           var val = getParse(el);
-          if(nullReplacement !== undefined && !val){
+          if(nullReplacement !== undefined && (val == null || val == undefined)){
             return nullReplacement;
           }
           return val;

test/spec/filter/collection/group-by.js

@@ -83,14 +83,16 @@ describe('groupByFilter', function() {
       {name: 'Paula', team: 'beta'},
       {name: 'Scruath', team: 'gamma'},
       {name: 'Alex', team: null },
-      {name: 'Rob' }
+      {name: 'Rob' },
+      {name: 'Sven', team: false }
     ];
 
     expect(filter(players, 'team', 'a')).toEqual( {
       a: [players[5], players[6]],
       alpha: [players[0]],
       beta: [players[1], players[3]],
-      gamma: [players[2], players[4]]
+      gamma: [players[2], players[4]],
+      'false': [players[7]]
     });
 
   });