homeio

1import "server-only";
2
3type CacheEntry<T> = {
4  value: T;
5  expiresAt: number;
6};
7
8export class LruCache<T> {
9  private readonly entries = new Map<string, CacheEntry<T>>();
10
11  constructor(
12    private readonly maxEntries: number,
13    private readonly defaultTtlMs: number,
14  ) {}
15
16  get(key: string): T | null {
17    const entry = this.entries.get(key);
18    if (!entry) return null;
19
20    if (entry.expiresAt <= Date.now()) {
21      this.entries.delete(key);
22      return null;
23    }
24
25    this.entries.delete(key);
26    this.entries.set(key, entry);
27    return entry.value;
28  }
29
30  set(key: string, value: T, ttlMs = this.defaultTtlMs): void {
31    if (this.entries.has(key)) {
32      this.entries.delete(key);
33    }
34
35    this.entries.set(key, {
36      value,
37      expiresAt: Date.now() + ttlMs,
38    });
39
40    if (this.entries.size > this.maxEntries) {
41      const oldestKey = this.entries.keys().next().value;
42      if (oldestKey) {
43        this.entries.delete(oldestKey);
44      }
45    }
46  }
47
48  delete(key: string): void {
49    this.entries.delete(key);
50  }
51
52  clear(): void {
53    this.entries.clear();
54  }
55}
56