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

  words.forEach(word => {
    const firstLetter = word.charAt(0).toLowerCase();

    if(!groups[firstLetter]) groups[firstLetter] = [];
    
    groups[firstLetter].push(word);
  })

  return groups;
}

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