save/retrieve state in the query string

save_retrieve.js

function saveParamsToUrlQuery(state) {
  const queryString = Object.keys(state)
    .reduce((res, key) => state[key] ?
      res += `${encodeURIComponent(key)}=${encodeURIComponent(state[key])}&` :
      res,
    '');
  history.pushState({}, 'generate-routes', window.location.pathname + '?' + queryString);
}

function loadInputFromUrl() {
  const queryStrings = (window.location.search.split('?')[1] || '').split('&');
  return queryStrings.reduce((result, qs) => {
    const f = qs.split('=');
    result[decodeURIComponent(f[0])] = decodeURIComponent(f[1]);
    return result;
  }, {});
}