diff --git a/index.js b/index.js
index 0116fbe..d8b8442 100644
--- a/index.js
+++ b/index.js
@@ -62,7 +62,7 @@ module.exports = {
     'no-misleading-character-class': 'error',
     'no-new-symbol': 'error',
     'no-obj-calls': 'error',
-    'no-promise-executor-return': 'warn',
+    // 'no-promise-executor-return': 'warn',
     'no-prototype-builtins': 'error',
     'no-self-assign': 'error',
     'no-self-compare': 'warn',
@@ -70,7 +70,7 @@ module.exports = {
     'no-sparse-arrays': 'error',
     // 'no-template-curly-in-string': 'warn',
     'no-this-before-super': 'error',
-    // 'no-undef': 'error',
+    'no-undef': 'error',
     'no-unexpected-multiline': 'error',
     // 'no-unmodified-loop-condition': 'warn',
     'no-unreachable': 'warn',
diff --git a/package.json b/package.json
index f9db484..f3cf516 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@sup39/eslint-config-basic",
-  "version": "0.1.0",
+  "version": "0.1.2",
   "main": "index.js",
   "license": "MIT",
   "files": [