diff --git a/tools/upend_js/.gitignore b/tools/upend_js/.gitignore
index 6d6f8ec..1c23382 100644
--- a/tools/upend_js/.gitignore
+++ b/tools/upend_js/.gitignore
@@ -1,2 +1,3 @@
 node_modules
 *.wasm
+*.js