diff --git a/tools/build/build.py b/tools/build/build.py
index f35a9d25..fa7f6a00 100755
--- a/tools/build/build.py
+++ b/tools/build/build.py
@@ -106,7 +106,7 @@ def build_oxjs(downloads=False, geo=False):
     for filename in filenames[1]:
         ox_files[1].append(js_dir + filename)
     filenames = filenames[0] + filenames[1]
-    for filename in os.listdir(source_path + js_dir):
+    for filename in sorted(os.listdir(source_path + js_dir)):
         if not filename in filenames \
                 and not filename.startswith('.') \
                 and not filename.endswith('~'):