A comparison of using lodash vs not using it.

lodash-comparison.js

/**
 * With lodash
 */

const fetchDestinationsFor = (city, excludeUncommon, sortFn) => {
    const chain = _.chain(city)
      .result('destinations', [])
      .filter(excludeUncommon ? (x => x.common == true) : (x => true))
      .map(x => fetchBySlug(x.reference))
      .sortBy(sortFn || (x => true));

    return chain.value();
};

/**
 * Without lodash
 */

const fetchDestinationsFor = (city, excludeUncommon, sortFn) => {
  // get desintations
  let references = [];
  if (city && city.destinations) {
    references = city.destinations;
  }
 
  // exclude uncommon destinations
  if (excludeUncommon) {
    var newReferences = [];
    for (var i = 0; i < references.length; i++) {
      if (references[i].common == true) {
        newReferences.push(references[i])
      }
    }
    references = newReferences;
  }
 
  // replace list of references with the actual destination object
  // this can be replaced with map() if you don't have to support IE8
  var formatted = [];
  for (var i = 0; i < references.length; i++) {
    formatted.push(fetchBySlug(x.reference))
  }
 
  // thankfully Array.sort() is widley supported
  return formatted.sort(sortFn || (x => true));
};