Layouts

So far, we've treated pages as entirely standalone components — upon navigation, the existing component will be destroyed, and a new one will take its place.

But in many apps, there are elements that should be visible on every page, such as top-level navigation or a footer. Instead of repeating them in every page, we can use layout components.

To create a layout component that applies to every page, make a file called src/routes/__layout.svelte. The default layout component (the one that SvelteKit uses if you don't bring your own) looks like this...

<slot></slot>

...but we can add whatever markup, styles and behaviour we want. The only requirement is that the component includes a <slot> for the page content. For example, let's add a nav bar:

<!-- src/routes/__layout.svelte -->
<nav>
	<a href="/">Home</a>
	<a href="/about">About</a>
	<a href="/settings">Settings</a>
</nav>

<slot></slot>

If we create pages for /, /about and /settings...

<!-- src/routes/index.svelte -->
<h1>Home</h1>

<!-- src/routes/about.svelte -->
<h1>About</h1>

<!-- src/routes/settings.svelte -->
<h1>Settings</h1>

...the nav will always be visible, and clicking between the three pages will only result in the <h1> being replaced.

Nested layoutspermalink

Suppose we don't just have a single /settings page, but instead have nested pages like /settings/profile and /settings/notifications with a shared submenu (for a real-life example, see github.com/settings).

We can create a layout that only applies to pages below /settings (while inheriting the root layout with the top-level nav):

<!-- src/routes/settings/__layout.svelte -->
<h1>Settings</h1>

<div class="submenu">
	<a href="/settings/profile">Profile</a>
	<a href="/settings/notifications">Notifications</a>
</div>

<slot></slot>

Resetspermalink

To reset the layout stack, create a __layout.reset.svelte file instead of a __layout.svelte file. For example, if you want your /admin/* pages to not inherit the root layout, create a file called src/routes/admin/__layout.reset.svelte.

Layout resets are otherwise identical to normal layout components.

Error pagespermalink

If a page fails to load (see Loading), SvelteKit will render an error page. You can customise this page by creating __error.svelte components alongside your layout and page components.

For example, if src/routes/settings/notifications/index.svelte failed to load, SvelteKit would render src/routes/settings/notifications/__error.svelte in the same layout, if it existed. If not, it would render src/routes/settings/__error.svelte in the parent layout, or src/routes/__error.svelte in the root layout.

SvelteKit provides a default error page in case you don't supply src/routes/__error.svelte, but it's recommended that you bring your own.

// declaration type
// * also see type for `LoadOutput` in the Loading section

export interface ErrorLoadInput<Params extends Record<string, string> = Record<string, string>>
	extends LoadInput<Params> {
	status?: number;
	error?: Error;
}

If an error component has a load function, it will be called with error and status properties:

<script context="module">
	/** @type {import('@sveltejs/kit').ErrorLoad} */
	export function load({ error, status }) {
		return {
			props: {
				title: `${status}: ${error.message}`
			}
		};
	}
</script>

<script>
	export let title;
</script>

<h1>{title}</h1>

Layout components also have access to error and status via the page store

Server-side stack traces will be removed from error in production, to avoid exposing privileged information to users.