Updated SvelteKit example. (#7301)

examples/sveltekit/src/hooks.js

@@ -0,0 +1,20 @@
+import cookie from 'cookie';
+import { v4 as uuid } from '@lukeed/uuid';
+
+export const handle = async ({ request, resolve }) => {
+	const cookies = cookie.parse(request.headers.cookie || '');
+	request.locals.userid = cookies.userid || uuid();
+
+	const response = await resolve(request);
+
+	if (!cookies.userid) {
+		// if this is the first time the user has visited this app,
+		// set a cookie so that we recognise them when they return
+		response.headers['set-cookie'] = cookie.serialize('userid', request.locals.userid, {
+			path: '/',
+			httpOnly: true
+		});
+	}
+
+	return response;
+};