LRU Cache LeetCode solution in JavaScript

1
/**
2
 * @param {number} capacity
3
 */
4
var LRUCache = function (capacity) {
5
  this.capacity = capacity;
6
  this.cache = new Map();
7
};
8

9
/**
10
 * @param {number} key
11
 * @return {number}
12
 */
13
LRUCache.prototype.get = function (key) {
14
  if (!this.cache.has(key)) {
15
    return -1;
16
  }
17

18
  let val = this.cache.get(key);
19
  this.cache.delete(key);
20
  this.cache.set(key, val);
21
  return val;
22
};
23

24
/**
25
 * @param {number} key
26
 * @param {number} value
27
 * @return {void}
28
 */
29
LRUCache.prototype.put = function (key, value) {
30
  if (this.cache.has(key)) {
31
    this.cache.delete(key);
32
  } else {
33
    if (this.cache.size >= this.capacity) {
34
      let [lastElm] = this.cache.keys();
35
      this.cache.delete(lastElm);
36
    }
37
  }
38
  this.cache.set(key, value);
39
};
40

41
/**
42
 * Your LRUCache object will be instantiated and called as such:
43
 * var obj = new LRUCache(capacity)
44
 * var param_1 = obj.get(key)
45
 * obj.put(key,value)
46
 */