fix: ignore profile picture cache after profile picture gets updated

frontend/src/lib/utils/profile-picture-util.ts

@@ -0,0 +1,38 @@
+import { browser } from '$app/environment';
+
+type SkipCacheUntil = {
+	[key: string]: number;
+};
+
+export function getProfilePictureUrl(userId?: string) {
+	if (!userId) return '';
+
+	let url = `/api/users/${userId}/profile-picture.png`;
+
+	if (browser) {
+		const skipCacheUntil = getSkipCacheUntil(userId);
+		const skipCache = skipCacheUntil > Date.now();
+		if (skipCache) {
+			const skipCacheParam = new URLSearchParams();
+			skipCacheParam.append('skip-cache', skipCacheUntil.toString());
+			url += '?' + skipCacheParam.toString();
+		}
+	}
+
+	return url.toString();
+}
+
+function getSkipCacheUntil(userId: string) {
+	const skipCacheUntil: SkipCacheUntil = JSON.parse(
+		localStorage.getItem('skip-cache-until') ?? '{}'
+	);
+	return skipCacheUntil[userId] ?? 0;
+}
+
+export function bustProfilePictureCache(userId: string) {
+	const skipCacheUntil: SkipCacheUntil = JSON.parse(
+		localStorage.getItem('skip-cache-until') ?? '{}'
+	);
+	skipCacheUntil[userId] = Date.now() + 1000 * 60 * 15; // 15 minutes
+	localStorage.setItem('skip-cache-until', JSON.stringify(skipCacheUntil));
+}