diff --git a/.babelrc b/.babelrc
index 832059455..a96fd673e 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,3 +1,6 @@
 {
     "presets": [["@babel/preset-flow", { "all": true }]]
-  }
\ No newline at end of file
+    
+  }
+  
+  
\ No newline at end of file
diff --git a/package.json b/package.json
index 8ffeeef92..beceb0ba9 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,8 @@
         "test": "npx tsc && nyc --reporter=html --reporter=text-summary mocha",
         "coverage": "nyc report --reporter=text-lcov > ./coverage/lcov.info",
         "coveralls": "nyc report --reporter=text-lcov | coveralls && rm -r coverage",
-        "build": "babel src/ -d dist/"
+        "build": "babel src/ -d dist/",
+        "flow": "flow"
     },
     "nyc": {
         "exclude": [
@@ -166,6 +167,7 @@
         "eslint": "^8.31.0",
         "eslint-config-nodebb": "^0.2.1",
         "eslint-plugin-import": "2.26.0",
+        "flow-bin": "^0.219.2",
         "grunt": "1.5.3",
         "grunt-contrib-watch": "1.1.0",
         "husky": "8.0.2",
diff --git a/src/controllers/category.js b/src/controllers/category.js
index 5004cafca..4a34e2d40 100644
--- a/src/controllers/category.js
+++ b/src/controllers/category.js
@@ -1,3 +1,5 @@
+// @flow
+
 'use strict';