interface Item {
  category: string;
  value: number;
}

function sumByCategory(items: Item[]): Record<string, number> {
  let group = {}
  items.forEach((v) => {
    const gkey = v.category
    if(!group[gkey]) group[gkey] = 0
    group[gkey] = group[gkey] + v.value
  })
 return group
}

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