diff --git a/package.json b/package.json
index f89b985..bccb63b 100644
--- a/package.json
+++ b/package.json
@@ -37,6 +37,7 @@
   "author": "Google, LLC",
   "license": "Apache-2.0",
   "devDependencies": {
+    "@babel/plugin-proposal-private-methods": "^7.18.6",
     "@compodoc/compodoc": "^1.1.9",
     "@types/cors": "^2.8.6",
     "@types/express": "^4.16.1",