initial commit

src/app.tsx

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+import * as React from "react";
+
+export function App() {
+	return <h1 className="text-3xl">Hello world!</h1>;
+}

src/lib/assert.ts

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+export class AssertionError extends Error {
+	constructor(msg?: string) {
+		super(msg);
+		this.name = "AssertionError";
+	}
+}
+
+export function assert(
+	condition: unknown,
+	message?: string,
+): asserts condition {
+	if (Boolean(condition)) return;
+	const parts = ["assertion failed", message].filter(
+		(v) => v !== undefined,
+	);
+	throw new AssertionError(parts.join(": "));
+}

src/main.tsx

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+import * as React from "react";
+import { createRoot } from "react-dom/client";
+import { App } from "./app";
+import { assert } from "./lib/assert";
+
+import "./style.pcss";
+
+const root = document.getElementById("root");
+assert(root, "document doesn't contain any #root element");
+
+createRoot(root).render(
+	<React.StrictMode>
+		<App />
+	</React.StrictMode>,
+);

src/style.pcss

@@ -0,0 +1 @@
+@import "tailwindcss";