Round 16: Peer Assessment, Emergency Contacts, School Events, School Branding, Email Templates, Performance, Styling Polish, Onboarding 24 Steps

src/lib/cache.ts

@@ -0,0 +1,79 @@
+// CompetenceTrack — In-memory API response cache utility
+// Provides TTL-based caching for API responses to reduce redundant fetches
+
+interface CacheEntry<T> {
+  data: T;
+  timestamp: number;
+  ttl: number; // time to live in ms
+}
+
+const cache = new Map<string, CacheEntry<any>>();
+
+/**
+ * Get cached data or fetch and cache it.
+ * If the cache entry exists and is not expired, returns cached data.
+ * Otherwise, calls the fetcher, caches the result, and returns it.
+ */
+export function getCached<T>(key: string, fetcher: () => Promise<T>, ttlMs: number = 30000): Promise<T> {
+  const entry = cache.get(key);
+  if (entry && Date.now() - entry.timestamp < entry.ttl) {
+    return Promise.resolve(entry.data as T);
+  }
+
+  return fetcher().then((data) => {
+    cache.set(key, { data, timestamp: Date.now(), ttl: ttlMs });
+    return data;
+  });
+}
+
+/**
+ * Invalidate a specific cache entry by key.
+ */
+export function invalidateCache(key: string): void {
+  cache.delete(key);
+}
+
+/**
+ * Invalidate all cache entries whose key matches a pattern.
+ * Pattern uses simple wildcard: '*' matches any characters.
+ * Example: invalidateCachePattern('dashboard:*') clears all keys starting with 'dashboard:'
+ */
+export function invalidateCachePattern(pattern: string): void {
+  const regexStr = pattern.replace(/\*/g, '.*');
+  const regex = new RegExp(`^${regexStr}$`);
+  for (const key of cache.keys()) {
+    if (regex.test(key)) {
+      cache.delete(key);
+    }
+  }
+}
+
+/**
+ * Clear all cache entries.
+ */
+export function clearCache(): void {
+  cache.clear();
+}
+
+/**
+ * Get cache stats for debugging.
+ */
+export function getCacheStats(): { size: number; keys: string[] } {
+  return {
+    size: cache.size,
+    keys: [...cache.keys()],
+  };
+}
+
+// Default TTLs for different API types
+export const CACHE_TTL = {
+  DASHBOARD: 30000,     // 30s
+  ANALYTICS: 60000,     // 60s
+  NOTIFICATIONS: 15000, // 15s
+  SCHOOL_YEARS: 120000, // 120s
+  COMPETENCY_TEMPLATES: 120000, // 120s
+  CLASSES: 60000,       // 60s
+  STUDENTS: 60000,      // 60s
+  ATTENDANCE: 30000,    // 30s
+  ASSESSMENTS: 45000,   // 45s
+} as const;