LRU cache

LRUcache.js

export class LRUCache extends Map {
    constructor(maxSize) {
        if (maxSize <= 0) {
            throw new Error('maxSize must be greater than 0');
        }
        super();
        this.maxSize = maxSize;
    }
    set(key, value) {
        super.delete(key);
        super.set(key, value);
        if (this.size > this.maxSize) {
            const keyToDelete = this.keys().next().value;
            if (keyToDelete !== undefined) {
                this.delete(keyToDelete);
            }
        }
        return this;
    }
    get(key) {
        const value = super.get(key);
        if (value !== undefined) {
            // Deleting and setting the value again ensures the key is at the end of the LRU queue
            this.delete(key);
            this.set(key, value);
        }
        return value;
    }
}

LRUcache.ts

export class LRUCache<K, V> extends Map<K, V> {
  constructor(public readonly maxSize: number) {
    if (maxSize <= 0) {
      throw new Error('maxSize must be greater than 0');
    }
    super();
  }

  override set(key: K, value: V): this {
    super.delete(key);
    super.set(key, value);
    if (this.size > this.maxSize) {
      const keyToDelete = this.keys().next().value;
      if (keyToDelete !== undefined) {
        this.delete(keyToDelete);
      }
    }
    return this;
  }

  override get(key: K): V | undefined {
    const value = super.get(key);
    if (value !== undefined) {
      // Deleting and setting the value again ensures the key is at the end of the LRU queue
      this.delete(key);
      this.set(key, value);
    }
    return value;
  }
}