/**
 * Exemplo:
 * const object = {a: 1, b: 2, c: 3};
 * const keys = ["a", "c"];
 * filter(object, keys);
 * //=> {a: 1, c: 3}
 */
function filter(object = [], keys = []) {
  if (typeof object !== "object") throw new Error("must be an object");

  if (!Array.isArray(keys)) throw new Error("must be an array");

  if (!keys.every(key => typeof key === "string")) throw new Error("must be an array of strings");

  const newObject = {};

  keys.forEach(key => {
    const value = object[key];

    if (value) newObject[key] = value;
  });

  return newObject;
}