diff --git a/tsconfig.json b/tsconfig.json
index 1b4e6cd..cf0f8ac 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,6 +2,7 @@
   "compilerOptions": {
     "target": "es5",
     "lib": [
+      "es6",
       "dom",
       "dom.iterable",
       "esnext"