fix: add link rel=preload for exported sites

test/apps/export-webpack/src/routes/_error.svelte

@@ -0,0 +1,3 @@
+<h1>{status}</h1>
+
+<p>{error.message}</p>

test/apps/export-webpack/src/routes/blog/[slug].html

@@ -0,0 +1,13 @@
+<script context="module">
+	export function preload({ params }) {
+		return this.fetch(`blog/${params.slug}.json`).then(r => r.json()).then(post => {
+			return { post };
+		});
+	}
+</script>
+
+<script>
+	export let post;
+</script>
+
+<h1>{post.title}</h1>

test/apps/export-webpack/src/routes/blog/[slug].json.js

@@ -0,0 +1,19 @@
+import posts from './_posts.js';
+
+export function get(req, res) {
+	const post = posts.find(post => post.slug === req.params.slug);
+
+	if (post) {
+		res.writeHead(200, {
+			'Content-Type': 'application/json'
+		});
+
+		res.end(JSON.stringify(post));
+	} else {
+		res.writeHead(404, {
+			'Content-Type': 'application/json'
+		});
+
+		res.end(JSON.stringify({ message: 'not found' }));
+	}
+}

test/apps/export-webpack/src/routes/blog/_posts.js

@@ -0,0 +1,5 @@
+export default [
+	{ slug: 'foo', title: 'once upon a foo' },
+	{ slug: 'bar', title: 'a bar is born' },
+	{ slug: 'baz', title: 'bazzily ever after' }
+];

test/apps/export-webpack/src/routes/blog/index.html

@@ -0,0 +1,17 @@
+<script context="module">
+	export function preload() {
+		return this.fetch('blog.json').then(r => r.json()).then(posts => {
+			return { posts };
+		});
+	}
+</script>
+
+<script>
+	export let posts;
+</script>
+
+<h1>blog</h1>
+
+{#each posts as post}
+	<p><a href="blog/{post.slug}">{post.title}</a></p>
+{/each}

test/apps/export-webpack/src/routes/blog/index.json.js

@@ -0,0 +1,9 @@
+import posts from './_posts.js';
+
+export function get(req, res) {
+	res.writeHead(200, {
+		'Content-Type': 'application/json'
+	});
+
+	res.end(JSON.stringify(posts));
+}

test/apps/export-webpack/src/routes/index.svelte

@@ -0,0 +1,4 @@
+<h1>Great success!</h1>
+
+<a href="blog">blog</a>
+<a href="">empty anchor</a>