Because SvelteKit uses directory-based routing, it’s easy to place modules and components alongside the routes that use them. A good rule of thumb is ‘put code close to where it’s used’.

Sometimes, code is used in multiple places. When this happens, it’s useful to have a place to put them that can be accessed by all routes without needing to prefix imports with ../../../../. In SvelteKit, that place is the src/lib directory. Anything inside this directory can be accessed by any module in src via the $lib alias.

Both +page.svelte files in this exercise import src/lib/message.js. But if you navigate to /a/deeply/nested/route, the app breaks, because we got the prefix wrong. Update it to use $lib/message.js instead:

<script>
	import { message } from '$lib/message.js';
</script>

<h1>a deeply nested route</h1>
<p>{message}</p>

<script lang="ts">
	import { message } from '$lib/message.js';
</script>

<h1>a deeply nested route</h1>
<p>{message}</p>

Do the same for src/routes/+page.svelte:

<script>
	import { message } from '$lib/message.js';
</script>

<h1>home</h1>
<p>{message}</p>

<script lang="ts">
	import { message } from '$lib/message.js';
</script>

<h1>home</h1>
<p>{message}</p>