const Filru = require('filru');
const require('request-promise-native'); // optional for loading async when not in cache
const handleErr = (err) => {
  throw err;
};

const maxBytes = 50 * 1024 * 1024; // 50 megabytes
const maxAge = 24 * 60 * 60 * 1000; // 1 day
const hashSeed = 'cache4gold'; // optional, random seed string
const pruneInterval = 1000 * 60 * 60; // optional, defaults to 1 hour
const f = new Filru({ dir: '/tmp/filru', maxBytes, maxAge, hashSeed, pruneInterval });

// optionally add a load function for when an object
// is not found in the cache
f.load = function customLoad(key) {
  // Custom async load function must return a promise.
  return request.get('https://my-site.com/' + key);
};

f.start()
  .then(() => {
    // fill the cache
    f.set('jimmy.txt', 'yo').catch(handleErr);
    f.get('jimmy.txt')
        .then((buffer) => {
          console.log('got jimmy:', buffer.toString('utf8')); // "yo"
        })
        .catch(handleErr);
    // stop cleanup job
    f.stop();
  })
  .catch(err => {
    throw err;
  });