diff --git a/src/kiss/Prelude.hx b/src/kiss/Prelude.hx
index 155a49e..d6a426e 100644
--- a/src/kiss/Prelude.hx
+++ b/src/kiss/Prelude.hx
@@ -544,17 +544,19 @@ class Prelude {
     private static var kissProcess:Process = null;
     #end
 
-    public static function walkDirectory(basePath, directory, processFile:(String) -> Void, ?processFolderBefore:(String) -> Void,
+    public static function walkDirectory(basePath, directory, processFile:(String) -> Void, ?filterFolderBefore:(String) -> Bool,
             ?processFolderAfter:(String) -> Void) {
         #if (sys || hxnodejs)
         for (fileOrFolder in FileSystem.readDirectory(joinPath(basePath, directory))) {
             switch (fileOrFolder) {
                 case folder if (FileSystem.isDirectory(joinPath(basePath, directory, folder))):
                     var subdirectory = joinPath(directory, folder);
-                    if (processFolderBefore != null) {
-                        processFolderBefore(subdirectory);
+                    if (filterFolderBefore != null) {
+                        if (filterFolderBefore(subdirectory)) {
+                            continue;
+                        }
                     }
-                    walkDirectory(basePath, subdirectory, processFile, processFolderBefore, processFolderAfter);
+                    walkDirectory(basePath, subdirectory, processFile, filterFolderBefore, processFolderAfter);
                     if (processFolderAfter != null) {
                         processFolderAfter(subdirectory);
                     }