LocalStorageProxy

localstorage-proxy.ts

type CacheItem = {
  now: number;
  value: string;
  maxAge: number;
};

class LocalStorageProxy {
  setItem(key: string, value: unknown, maxAge: number = 0) {
    localStorage.setItem(
      key,
      JSON.stringify({
        value,
        maxAge,
        now: Date.now(),
      })
    );
  }

  getItem(key: string): string | null {
    const item = localStorage.getItem(key);
    if (!item) return null;
    const cachedItem = JSON.parse(item) as CacheItem;
    const isExpired = Date.now() - cachedItem.now > cachedItem.maxAge;
    isExpired && this.removeItem(key);
    return isExpired ? null : cachedItem.value;
  }

  removeItem(key: string): void {
    localStorage.removeItem(key);
  }
}