Recover a secret string from random triplets

secret_string.txt

var recoverSecret = function(triplets) {
  let duplets = [];
  let res = '';
  triplets.forEach(trip =>  {
      duplets.push(trip.slice(0,2).join(''));
      duplets.push(trip.slice(1, 3).join(''));
  })
  duplets = duplets.filter((value, index, array) => array.indexOf(value) === index)
  let word = getWord(duplets);
  while(word) {
    res += word;
    duplets = duplets.filter(d => d.indexOf(word) === -1)
    word = getWord(duplets);
  }
  return res;
}

const getWord =  function(duplets) {
  let word = duplets.find(duplet => duplets.every(dup => dup[1] !== duplet[0]))
  return duplets.length > 1 ? word[0] : duplets[0]
    
}