LRU-кэш

1class LRUCache {
2  private map = new Map<string, number>()
3 
4  constructor(private capacity: number) {}
5 
6  get(key: string): number | undefined {
7    if (!this.map.has(key)) return undefined
8    const value = this.map.get(key)!
9    this.map.delete(key)
10    this.map.set(key, value) // переустановка = «недавно использован»
11    return value
12  }
13 
14  put(key: string, value: number): void {
15    this.map.delete(key)
16    this.map.set(key, value)
17    if (this.map.size > this.capacity) {
18      const oldest = this.map.keys().next().value
19      this.map.delete(oldest)
20    }
21  }
22}