Class InMemoryCache

apps/web/lib/cache.ts:1–33

export class InMemoryCache<TValue> {
  public readonly ttl: number;
  private readonly map: Map<string, { exp: number; value: TValue }>;
  constructor(opts: { ttl: number }) {
    this.ttl = opts.ttl;
    this.map = new Map();

    setInterval(() => {
      const now = Date.now();
      this.map.forEach(({ exp }, key) => {
        if (exp < now) {
          this.map.delete(key);
        }
      });
    }, 60_000);
  }

  public set(key: string, value: TValue) {
    this.map.set(key, { exp: Date.now() + this.ttl, value });
  }

  public get(key: string): TValue | null {
    const data = this.map.get(key);
    if (!data) {
      return null;
    }
    if (data.exp < Date.now()) {
      this.map.delete(key);
      return null;
    }
    return data.value;
  }
}