class Cache<T> {
  private items: Map<string, { value: T; expiration: number }>;
  private ttl: number;

  constructor(ttl: number) {
    this.items = new Map();
    this.ttl = ttl;
  }

  // Add an item to the cache
  set(key: string, value: T): void {
    const expiration = Date.now() + this.ttl;
    this.items.set(key, { value, expiration });

    // Auto-remove expired items
    setTimeout(() => {
      if (this.items.has(key) && this.items.get(key)!.expiration <= Date.now()) {
        this.items.delete(key);
      }
    }, this.ttl);
  }

  // Retrieve an item from the cache
  get(key: string): T | undefined {
    const item = this.items.get(key);
    if (!item || item.expiration <= Date.now()) {
      this.items.delete(key);
      return undefined;
    }
    return item.value;
  }

  // Remove an item
  delete(key: string): void {
    this.items.delete(key);
  }

  // Check if the cache contains a key
  has(key: string): boolean {
    return this.items.has(key);
  }
}

// Example usage
const cache = new Cache<string>(5000); // TTL: 5 seconds
cache.set("key1", "value1");

setTimeout(() => {
  const value = cache.get("key1");
  console.log(value ? `Value: ${value}` : "Key not found or expired");
}, 3000);

setTimeout(() => {
  const value = cache.get("key1");
  console.log(value ? `Value: ${value}` : "Key not found or expired");
}, 6000);