1class QueryCache {
2    #cache = new Map();
3    #maxSize;
4    #accessLog = new Map();
5
6    constructor(maxSize = 3) {
7        this.#maxSize = maxSize;
8    }
9
10    set(key, value) {
11        if (this.#cache.size >= this.#maxSize && !this.#cache.has(key)) {
12            const leastUsed = this.#findLeastUsed();
13            this.#cache.delete(leastUsed);
14            this.#accessLog.delete(leastUsed);
15        }
16        
17        this.#cache.set(key, value);
18        this.#updateAccess(key);
19    }
20
21    get(key) {
22        if (this.#cache.has(key)) {
23            this.#updateAccess(key);
24            return this.#cache.get(key);
25        }
26        return null;
27    }
28
29    #updateAccess(key) {
30        this.#accessLog.set(key, Date.now());
31    }
32
33    #findLeastUsed() {
34        let leastUsedKey = null;
35        let leastUsedTime = Infinity;
36
37        for (const [key, time] of this.#accessLog) {
38            if (time < leastUsedTime) {
39                leastUsedTime = time;
40                leastUsedKey = key;
41            }
42        }
43
44        return leastUsedKey;
45    }
46
47    getState() {
48        return Array.from(this.#cache.entries());
49    }
50}
51
52const cache = new QueryCache(3);
53cache.set('query1', 'result1');
54cache.set('query2', 'result2');
55cache.set('query3', 'result3');
56cache.get('query1');
57cache.set('query4', 'result4');
58
59console.log(cache.getState());