sameCharsWords.js

function getSameCharStrings(strings) {
  const repeatedCharsOrSpaceRegex = /(\w)(?=.*\1)|\s/g;
  const uniqueSortedChars = strings.map(word => {
    return word
      .replace(repeatedCharsOrSpaceRegex, '')
      .split('')
        .sort()
        .join('');
  });
  
  const indexes = uniqueSortedChars.reduce((currentIndexes, chars, index) => {
    currentIndexes[chars] = currentIndexes[chars] || [];
    currentIndexes[chars].push(index);

    return currentIndexes;
  }, {});

  return Object.keys(indexes)
    .filter(key => indexes[key].length >= 2)
    .map(key => {
      return indexes[key].map(index => strings[index]);
    });
}

// getSameCharStrings(['alllo', 'ooooiiio', 'be ee', 'alo', 'loa', 'be', 'io', 'sad'])

/* Results
 * [
 *   ['alllo', 'alo', 'loa'],
 *   ['ooooiiio', 'io'],
 *   ['be ee', 'be']
 * ];
 */