function groupByFirstLetter(words: string[]): Record<string, string[]> {
  let groupedByFirstLetter = {};
  for (let word of words) {
    if (!Object.hasOwn(groupedByFirstLetter, word[0].toLowerCase())) {
      groupedByFirstLetter[word[0].toLowerCase()] = [word];
    }
    else groupedByFirstLetter[word[0].toLowerCase()].push(word);
  }
  return groupedByFirstLetter;
}

// No modificar: necesario para evaluar el resultado.
export { groupByFirstLetter };