diff --git a/package.json b/package.json
index bed0573..72df8c3 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "doctoc": "^1.2.0",
     "nyc": "^8.4.0",
     "standard": "^8.5.0",
-    "uglify-js": "^2.6.4",
+    "uglify-js": "^3.8.0",
     "umd": "^3.0.1"
   },
   "files": [