LRU cache in TypeScript

LruCache.ts

class LruCache<T> {
  private values = new Map<string, T>();

  constructor(private maxEntries = 10) {}

  public get(key: string): T | undefined {
    const entry = this.values.get(key);
    if (entry != undefined) {
      this.values.delete(key);
      this.values.set(key, entry);
    }
    return entry;
  }

  public set(key: string, value: T): void {
    if (this.values.size >= this.maxEntries) {
      const keyToDelete = this.values.keys().next().value as string;
      this.values.delete(keyToDelete);
    }
    this.values.delete(key);
    this.values.set(key, value);
  }
}