class LRUCache { constructor () { this.max = 1000 this.map = new Map() } get (key) { const value = this.map.get(key) if (value === undefined) { return undefined } else { // Remove the key from the map and add it to the end this.map.delete(key) this.map.set(key, value) return value } } delete (key) { return this.map.delete(key) } set (key, value) { const deleted = this.delete(key) if (!deleted && value !== undefined) { // If cache is full, delete the least recently used item if (this.map.size >= this.max) { const firstKey = this.map.keys().next().value this.delete(firstKey) } this.map.set(key, value) } return this } } module.exports = LRUCache