diff --git a/package.json b/package.json
index d3be5e6..32a7b25 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "@babel/plugin-external-helpers": "^7.2.0",
     "@babel/plugin-transform-parameters": "^7.2.0",
     "@babel/preset-env": "^7.3.1",
-    "@babel/polyfill": "^7.2.5"
+    "@babel/polyfill": "^7.2.5",
     "autobahn": "^18.10.2",
     "rollup": "^1.1.2",
     "rollup-plugin-babel": "^4.3.2",