First attempt to add Google Analytics to SvelteKit. This should be per site.

src/lib/analytics.svelte

@@ -0,0 +1,39 @@
+<script lang="ts">
+// import { page } from '$app/stores'
+
+export let site_google_tracking_id: string = '';
+console.log(`site_google_tracking_id = `, site_google_tracking_id);
+
+if (typeof window !== 'undefined') {
+    window.dataLayer = window.dataLayer || [];
+    window.gtag = function gtag(): void {
+        window.dataLayer.push(arguments);
+    };
+    window.gtag('js', new Date());
+    window.gtag('config', site_google_tracking_id);
+}
+
+// $: if (typeof gtag !== 'undefined') {
+//     gtag('config', site_google_tracking_id, {
+//         page_title: document.title,
+//         page_path: $page.url.pathname,
+//     })
+// }
+</script>
+
+<svelte:head>
+<script
+    async
+    src="https://www.googletagmanager.com/gtag/js?id={site_google_tracking_id}">
+</script>
+<!-- <script>
+    window.dataLayer = window.dataLayer || []
+
+    function gtag() {
+    dataLayer.push(arguments)
+    }
+
+    gtag('js', new Date())
+    gtag('config', site_google_tracking_id)
+</script> -->
+</svelte:head>