Update Navbar.js

Add Listener Cleanup

Author: leovoon

src/components/Navbar.js

@@ -23,9 +23,12 @@ function Navbar() {
 
   useEffect(() => {
     showButton();
+    window.addEventListener('resize', showButton);
+    return {
+      window.removeEventListener('resize', showButton)
+    }
   }, []);
 
-  window.addEventListener('resize', showButton);
 
   return (
     <>