Ярослав Вавилин

const data = {
  a: 1,
  b: 2,
  c: 3,
  d: 5
};

const updatedData = Object.entries(data).reduce((acc, item) => {
  const [key, value] = item;
  if (key === "b" || key === "c") {
    acc[key] = value;
  }
  return acc;
}, {});