cacheable.js

const store = {
  cache: {},
  expires: 0,
  ttl: '1h'
};

function cacheable(settings) {
  return function cache() {
    const now = Date.now();
    let isExpired = false;
    const cacheSize = Array.isArray(settings.cache)
      ? settings.cache.length
      : Object.keys(settings.cache).length;
    if (now >= settings.expires || cacheSize === 0) isExpired = true;
    if (isExpired) {
      settings.expires = now + ms(settings.ttl);
      settings.cache = Array.isArray(settings.cache) ? [] : {};
    }
    log('statsCache:cacheSize:%d:expiresInMins:%s',
      cacheSize,
      `${Math.round((settings.expires - now) / 60000)}`);
    return isExpired;
  };
}

const expired = cacheable(store);