diff --git a/docs/basic/useful-hooks.md b/docs/basic/useful-hooks.md
index dea956a0..8821ffc3 100644
--- a/docs/basic/useful-hooks.md
+++ b/docs/basic/useful-hooks.md
@@ -37,7 +37,7 @@ function App() {
 }
 
 // Hook
-function useLocalStorage<T>(key: string, initialValue: T) {
+function useLocalStorage<T>(key: string, initialValue: T) : [T, (value: T | ((val: T) => T)) => void] {
   // State to store our value
   // Pass initial state function to useState so logic is only executed once
   const [storedValue, setStoredValue] = useState<T>(() => {