146.js

/**
 * @param {number} capacity
 */
var LRUCache = function (capacity) {
  this.capacity = capacity;
  this.map = new Map();
};

/**
 * @param {number} key
 * @return {number}
 */
LRUCache.prototype.get = function (key) {
  if (this.map.has(key)) {
    const value = this.map.get(key);
    this.map.delete(key);
    this.map.set(key, value);
    return value;
  } else {
    return -1;
  }
};

/**
 * @param {number} key
 * @param {number} value
 * @return {void}
 */
LRUCache.prototype.put = function (key, value) {
  if (this.map.has(key)) {
    this.map.delete(key);
  } else if (this.capacity === this.map.size) {
    this.map.delete(this.map.keys().next().value);
  }
  this.map.set(key, value);
};

const cache = new LRUCache(2);
cache.put(1, 0);
cache.put(2, 2);
console.log(cache.get(1));
cache.put(3, 3);
console.log(cache.get(2));