function getRandomInt(min, max) {

  return Math.random() * (max - min) + min;

}

​

const search = (word, callback) => {

  const results = ['foo', 'bar', 'baz', 'baz2', 'etc', 'etc2'];

  const numberOfResults = getRandomInt(1, results.length);

  const randomTimeout = getRandomInt(1, 4);

  setTimeout(() => {

    callback(null, results.slice(0, numberOfResults));

  }, randomTimeout);

};

​

const display = (data) => {

  console.log('display', data);

  const el = document.querySelector('#display-panel');

  const msg = (typeof data === 'string') ? data : data.join(', ');

  el.textContent = msg;

};

​

const displaySearchResults = (error, results) => {

  if (error) {

    display('Search failed, please retry later.');

  } else {

    display(results);

  }

};

​

const word = 'cats';

​

// will display random results each time

// uncomment to check

// search(word, displaySearchResults);

​

const searchWrapper = (word, callback) => {

  const key = `search-${word}`;

  const results = sessionStorage.getItem(key);

  if (results) {

    // keeping things asynchronous

    setTimeout(() => callback(null, results), 1);

  } else {

    search(word, (error, res) => {

      if (error) { return callback(error); }

      // keeping the results in cache

      sessionStorage.setItem(key, res);

      callback(null, res);

    });

  }

};

​

// will always display the same results because they are cached

searchWrapper('cats', displaySearchResults);

​