prefetch links

src/lib/Link.svelte

@@ -0,0 +1,31 @@
+<script>
+    import { page } from '$app/stores';
+    export let href;
+    let pageHost;
+    page.subscribe(p => pageHost = p.host); // apparently this works?
+
+    function isLocal(url) {
+        if (url.startsWith('/')) {
+            return true;
+        }
+
+        try {
+            let parsed = new URL(url);
+            return parsed.host === pageHost;
+        }
+        catch {
+            return false;
+        }
+    }
+</script>
+
+<!-- we pass href explicitly so a11y doesn't scream at us -->
+{#if isLocal(href)}
+    <a sveltekit:prefetch {href} {...$$props}>
+        <slot></slot>
+    </a>
+{:else}
+    <a {href} {...$$props}>
+        <slot></slot>
+    </a>
+{/if}