diff --git a/src/spec/tsconfig.json b/src/spec/tsconfig.json
index 9ed804ccc..74d81a9a7 100644
--- a/src/spec/tsconfig.json
+++ b/src/spec/tsconfig.json
@@ -18,7 +18,8 @@
       "es2015.proxy",
       "es2018.promise",
       "es2016",
-      "es2017.object"
+      "es2017.object",
+      "es2018"
     ],
     "baseUrl": ".",
     "rootDir": "../",