feature/IO-3499-React-19 - Checkpoint

client/src/index.jsx

@@ -16,6 +16,7 @@ import "./utils/CleanAxios";
 // import * as amplitude from "@amplitude/analytics-browser";
 import { PostHogProvider } from "posthog-js/react";
 import posthog from "posthog-js";
+import { StrictMode } from "react";
 
 window.global ||= window;
 
@@ -77,6 +78,18 @@ function App() {
   );
 }
 
-ReactDOM.createRoot(document.getElementById("root")).render(<App />);
+const rootEl = document.getElementById("root");
+
+if (!rootEl) throw new Error('Missing root element: <div id="root" />');
+
+const appTree = import.meta.env.DEV ? (
+  <StrictMode>
+    <App />
+  </StrictMode>
+) : (
+  <App />
+);
+
+ReactDOM.createRoot(rootEl).render(appTree);
 
 reportWebVitals();