add solid-devtools

src/index.tsx

@@ -1,4 +1,10 @@
 import { render } from "solid-js/web";
 import App from "./App.js";
+import "solid-devtools";
 
 render(() => <App />, document.getElementById("root")!);
+
+if (import.meta.env.VITE_DEVTOOLS_OVERLAY === "true") {
+  const overlay = await import("@solid-devtools/overlay")
+  overlay.attachDevtoolsOverlay()
+}

src/overrides.d.ts

@@ -7,6 +7,10 @@ interface ImportMetaEnv {
    * The code reversion. It's recommended to be the git commit sha.
    */
   readonly VITE_CODE_VERSION?: string;
+  /**
+   * Attach the overlay (in the dev mode) if it's `"true"`.
+   */
+  readonly VITE_DEVTOOLS_OVERLAY?: string;
 }
 
 interface ImportMeta {