As we saw in the routing introduction, layouts are a way to share UI and data loading logic between different routes.

Sometimes it’s useful to use layouts without affecting the route — for example, you might need your /app and /account routes to be behind authentication, while your /about page is open to the world. We can do this with a route group, which is a directory in parentheses.

Create an (authed) group by renaming account to (authed)/account then renaming app to (authed)/app.

Now we can control access to these routes by creating src/routes/(authed)/+layout.server.js:

import { redirect } from '@sveltejs/kit';

export function load({ cookies, url }) {
	if (!cookies.get('logged_in')) {
		redirect(303, `/login?redirectTo=${url.pathname}`);
	}
}

If you try to visit these pages, you’ll be redirected to the /login route, which has a form action in src/routes/login/+page.server.js that sets the logged_in cookie.

We can also add some UI to these two routes by adding a src/routes/(authed)/+layout.svelte file:

<script>
	let { children } = $props();
</script>

<form method="POST" action="/logout">
	<button>log out</button>
</form>

<script lang="ts">
	let { children } = $props();
</script>

<form method="POST" action="/logout">
	<button>log out</button>
</form>