Simple Cache

export default class Cache {
  constructor(ttl = 300000) { // 5 Minutes
    this.ttl = ttl;
    this.expirations = new Map();
    this.cache = new Map();
  }

  isExpired(key) {
    return (!this.cache.has(key)) ||
    (this.cache.has(key) && (!this.expirations.has(key) || this.expirations.get(key) < Date.now()));
  }

  set(key, val) {
    if (this.isExpired(key)) {
      this.cache.set(key, val);
      this.expirations.set(key, Date.now() + this.ttl);
    }
  }

  get(key) {
    return this.cache.get(key);
  }

  has(key) {
    return !this.isExpired(key) && this.cache.has(key);
  }

  delete(key) {
    this.expire(key);
    this.cache.delete(key);
  }

  clear() {
    this.expireAll();
    this.cache.clear();
  }

  expire(key) {
    this.expirations.delete(key);
  }

  expireAll() {
    this.expirations.clear();
  }
}