Don't persist cache on reload (#4854)

frontend/__tests__/utils/cache.test.ts

@@ -8,7 +8,6 @@ describe("Cache", () => {
   const testTTL = 1000; // 1 second
 
   beforeEach(() => {
-    localStorage.clear();
     vi.useFakeTimers();
   });
 
@@ -16,17 +15,7 @@ describe("Cache", () => {
     vi.useRealTimers();
   });
 
-  it("sets data in localStorage with expiration", () => {
-    cache.set(testKey, testData, testTTL);
-    const cachedEntry = JSON.parse(
-      localStorage.getItem(`app_cache_${testKey}`) || "",
-    );
-
-    expect(cachedEntry.data).toEqual(testData);
-    expect(cachedEntry.expiration).toBeGreaterThan(Date.now());
-  });
-
-  it("gets data from localStorage if not expired", () => {
+  it("gets data from memory if not expired", () => {
     cache.set(testKey, testData, testTTL);
 
     expect(cache.get(testKey)).toEqual(testData);
@@ -39,7 +28,6 @@ describe("Cache", () => {
     vi.advanceTimersByTime(5 * 60 * 1000 + 1);
 
     expect(cache.get(testKey)).toBeNull();
-    expect(localStorage.getItem(`app_cache_${testKey}`)).toBeNull();
   });
 
   it("returns null if cached data is expired", () => {
@@ -47,28 +35,19 @@ describe("Cache", () => {
 
     vi.advanceTimersByTime(testTTL + 1);
     expect(cache.get(testKey)).toBeNull();
-    expect(localStorage.getItem(`app_cache_${testKey}`)).toBeNull();
   });
 
-  it("deletes data from localStorage", () => {
+  it("deletes data from memory", () => {
     cache.set(testKey, testData, testTTL);
     cache.delete(testKey);
-
-    expect(localStorage.getItem(`app_cache_${testKey}`)).toBeNull();
+    expect(cache.get(testKey)).toBeNull();
   });
 
-  it("clears all data with the app prefix from localStorage", () => {
+  it("clears all data with the app prefix from memory", () => {
     cache.set(testKey, testData, testTTL);
     cache.set("anotherKey", { data: "More data" }, testTTL);
     cache.clearAll();
-
-    expect(localStorage.length).toBe(0);
-  });
-
-  it("does not retrieve non-prefixed data from localStorage when clearing", () => {
-    localStorage.setItem("nonPrefixedKey", "should remain");
-    cache.set(testKey, testData, testTTL);
-    cache.clearAll();
-    expect(localStorage.getItem("nonPrefixedKey")).toBe("should remain");
+    expect(cache.get(testKey)).toBeNull();
+    expect(cache.get("anotherKey")).toBeNull();
   });
 });

frontend/src/utils/cache.ts

@@ -5,26 +5,17 @@ type CacheEntry<T> = {
 };
 
 class Cache {
-  private prefix = "app_cache_";
-
   private defaultTTL = 5 * 60 * 1000; // 5 minutes
 
-  /**
-   * Generate a unique key with prefix for local storage
-   * @param key The key to be stored in local storage
-   * @returns The unique key with prefix
-   */
-  private getKey(key: CacheKey): string {
-    return `${this.prefix}${key}`;
-  }
+  private cacheMemory: Record<string, string> = {};
 
   /**
-   * Retrieve the cached data from local storage
-   * @param key The key to be retrieved from local storage
-   * @returns The data stored in local storage
+   * Retrieve the cached data from memory
+   * @param key The key to be retrieved from memory
+   * @returns The data stored in memory
    */
   public get<T>(key: CacheKey): T | null {
-    const cachedEntry = localStorage.getItem(this.getKey(key));
+    const cachedEntry = this.cacheMemory[key];
     if (cachedEntry) {
       const { data, expiration } = JSON.parse(cachedEntry) as CacheEntry<T>;
       if (Date.now() < expiration) return data;
@@ -35,34 +26,34 @@ class Cache {
   }
 
   /**
-   * Store the data in local storage with expiration
-   * @param key The key to be stored in local storage
-   * @param data The data to be stored in local storage
+   * Store the data in memory with expiration
+   * @param key The key to be stored in memory
+   * @param data The data to be stored in memory
    * @param ttl The time to live for the data in milliseconds
    * @returns void
    */
   public set<T>(key: CacheKey, data: T, ttl = this.defaultTTL): void {
     const expiration = Date.now() + ttl;
     const entry: CacheEntry<T> = { data, expiration };
-    localStorage.setItem(this.getKey(key), JSON.stringify(entry));
+    this.cacheMemory[key] = JSON.stringify(entry);
   }
 
   /**
-   * Remove the data from local storage
-   * @param key The key to be removed from local storage
+   * Remove the data from memory
+   * @param key The key to be removed from memory
    * @returns void
    */
   public delete(key: CacheKey): void {
-    localStorage.removeItem(this.getKey(key));
+    delete this.cacheMemory[key];
   }
 
   /**
-   * Clear all data with the app prefix from local storage
+   * Clear all data
    * @returns void
    */
   public clearAll(): void {
-    Object.keys(localStorage).forEach((key) => {
-      if (key.startsWith(this.prefix)) localStorage.removeItem(key);
+    Object.keys(this.cacheMemory).forEach((key) => {
+      delete this.cacheMemory[key];
     });
   }
 }