diff --git a/ROADMAP.md b/ROADMAP.md
index 43aeb2c..4b50fcc 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -194,7 +194,7 @@
 - [ ] "no-throw-literal"
 - [ ] "no-trailing-spaces"
 - [ ] "no-undef"
-- [ ] "no-undef-init"
+- [X] "no-undef-init"
 - [X] "no-undefined"
 - [X] "no-underscore-dangle"
 - [ ] "no-unexpected-multiline"
diff --git a/src/rules/default.json b/src/rules/default.json
index 62d5ffe..aad6552 100644
--- a/src/rules/default.json
+++ b/src/rules/default.json
@@ -338,6 +338,9 @@
   "no-ternary": [
     "off"
   ],
+  "no-undef-init": [
+    "error"
+  ],
   "no-undefined": [
     "off"
   ],