diff --git a/tools/js2c.py b/tools/js2c.py
index bcfc4764a97..8685722c13c 100755
--- a/tools/js2c.py
+++ b/tools/js2c.py
@@ -183,8 +183,12 @@ TEMPLATE = """
 
 namespace node {{
 
+namespace {{
+
 {definitions}
 
+}}  // anonymous namespace
+
 v8::Local<v8::String> LoadersBootstrapperSource(Environment* env) {{
   return internal_bootstrap_loaders_value.ToStringChecked(env->isolate());
 }}