TypeScript Generic LRU Cache

interface CacheNode<K, V> { key: K; value: V; prev?: CacheNode<K, V>; next?: CacheNode<K, V>; } export class LRUCache<K, V> { private capacity: number; private map = new Map<K, CacheNode<K, V>>(); private head?: CacheNode<K, V>; private tail?: CacheNode<K, V>; constructor(capacity: number) { this.capacity = capacity; } public get(key: K): V | undefined { const node = this.map.get(key); if (!node) return undefined; this.detach(node); this.attachHead(node); return node.value; } private detach(node: CacheNode<K, V>): void { if (node.prev) node.prev.next = node.next; if (node.next) node.next.prev = node.prev; if (this.head === node) this.head = node.next; if (this.tail === node) this.tail = node.prev; } private attachHead(node: CacheNode<K, V>): void { node.next = this.head; node.prev = undefined; if (this.head) this.head.prev = node; this.head = node; if (!this.tail) this.tail = node; } }