diff --git a/src/_filter/collection/count-by.js b/src/_filter/collection/count-by.js
index 0be73e0..1964424 100644
--- a/src/_filter/collection/count-by.js
+++ b/src/_filter/collection/count-by.js
@@ -25,7 +25,7 @@ angular.module('a8m.count-by', [])
       collection.forEach( function( elm ) {
         prop = get(elm);
 
-        if(!result[prop]) {
+        if(!isArray(result[prop])) {
           result[prop] = 0;
         }
 
diff --git a/src/_filter/collection/group-by.js b/src/_filter/collection/group-by.js
index 5832098..aba7003 100644
--- a/src/_filter/collection/group-by.js
+++ b/src/_filter/collection/group-by.js
@@ -33,7 +33,7 @@ angular.module('a8m.group-by', [ 'a8m.filter-watcher' ])
         forEach( collection, function( elm ) {
           prop = getter(elm);
 
-          if(!result[prop]) {
+          if(!isArray(result[prop])) {
             result[prop] = [];
           }
           result[prop].push(elm);
diff --git a/src/_filter/string/repeat.js b/src/_filter/string/repeat.js
index 627d0ec..2b2cb43 100644
--- a/src/_filter/string/repeat.js
+++ b/src/_filter/string/repeat.js
@@ -30,8 +30,8 @@ angular.module('a8m.repeat', [])
  * @returns {*}
  */
 function strRepeat(str, n, sep) {
-  if(!n) {
+  if(!isNumber(n) || !n) {
     return str;
   }
   return str + sep + strRepeat(str, --n, sep);
-}
\ No newline at end of file
+}