function groupByFirstLetter(words: string[]): Record<string, string[]> {
  let obj: Record<string, string[]> = {};

  for (let word of words){
    let letter = word[0].toLowerCase();
    obj[letter] ??= [];
    obj[letter].push(word);
  }

  return obj;
}

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