Function for checking array of words for anagrams

anagram.js

/**
 * Function for checking array of words for anagrams
 * @param {Array} words Array of words
 * @return {Array} Array of arrays with anagram words
 */
const anagram = words => words.reduce((result, word) => {
  if (!result[word.length]) {
    result[word.length] = [word];
  }
  else {
    result[word.length].push(word);
  }
  
  return result;
}, [])
.map(words => words.reduce((result, word) => {
  var sorted = word.split('').sort().join('');
  
  if (!result[sorted]) {
    result[sorted] = [word];
  }
  else {
    result[sorted].push(word);
  }

  return result;
}, {}))
.map(words => Object.keys(words).map(key => words[key]))
.reduce((result, words) => {
  words.forEach(word => result.push(word));
  
  return result;
}, [])
.filter(words => words.length > 1);