function createUser(
  name,
  role = "viewer",
  permissions = { read: true, write: false },
  level = permissions.write ? 2 : 1
) {
  return { name, role, permissions, level };
}

const user1 = createUser("Carlos");
const user2 = createUser("Diana", "editor", { read: true, write: true });
const user3 = createUser("Eve", "admin", undefined, 5);

console.log(user1.role, user1.level);
console.log(user2.role, user2.level);
console.log(user3.role, user3.level);