diff --git a/package-lock.json b/package-lock.json
index 26d4f59..0d4c73f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@matrixai/lint",
-  "version": "0.4.8",
+  "version": "0.4.9",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@matrixai/lint",
-      "version": "0.4.8",
+      "version": "0.4.9",
       "license": "Apache-2.0",
       "dependencies": {
         "@eslint/compat": "^1.2.5",
diff --git a/package.json b/package.json
index 5f59c23..05e2609 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@matrixai/lint",
-  "version": "0.4.8",
+  "version": "0.4.9",
   "author": "Roger Qiu",
   "description": "Org wide custom eslint rules",
   "license": "Apache-2.0",
diff --git a/src/configs/eslint.ts b/src/configs/eslint.ts
index 50a90f5..ee8d38c 100644
--- a/src/configs/eslint.ts
+++ b/src/configs/eslint.ts
@@ -149,6 +149,21 @@ const config = [
           message: 'Use `globalThis` instead',
         },
       ],
+      'no-restricted-syntax': [
+        'error',
+        {
+          selector:
+            'Program > VariableDeclaration[kind="const"] > VariableDeclarator[id.type="Identifier"][init.type="ArrowFunctionExpression"]',
+          message:
+            'Top-level functions must be declarations: `function foo() {}`',
+        },
+        {
+          selector:
+            'Program > VariableDeclaration[kind="const"] > VariableDeclarator[id.type="Identifier"][init.type="FunctionExpression"]',
+          message:
+            'Top-level functions must be declarations: `function foo() {}`',
+        },
+      ],
       'prefer-rest-params': 0,
       'require-yield': 0,
       eqeqeq: ['error', 'smart'],