Add page permalink

web-frontend/src/lib/url.js

@@ -0,0 +1,37 @@
+// From: https://svelte.dev/repl/5abaac000b164aa1aacc6051d5c4f584?version=3.49.0
+import { derived, writable } from 'svelte/store';
+
+export function createUrlStore(ssrUrl) {
+	// Ideally a bundler constant so that it's tree-shakable
+	if (typeof window === 'undefined') {
+		const { subscribe } = writable(ssrUrl);
+		return { subscribe };
+	}
+
+	const href = writable(window.location.href);
+
+	const originalPushState = history.pushState;
+	const originalReplaceState = history.replaceState;
+
+	const updateHref = () => href.set(window.location.href);
+
+	history.pushState = function () {
+		originalPushState.apply(this, arguments);
+		updateHref();
+	};
+
+	history.replaceState = function () {
+		originalReplaceState.apply(this, arguments);
+		updateHref();
+	};
+
+	window.addEventListener('popstate', updateHref);
+	window.addEventListener('hashchange', updateHref);
+
+	return {
+		subscribe: derived(href, ($href) => new URL($href)).subscribe
+	};
+}
+
+// If you're using in a pure SPA, you can return a store directly and share it everywhere
+export default createUrlStore();