function createUser(name = 'Guest', age = 0, active = true) {
  return { name, age, active };
}

const users = [
  createUser('Sarah', 25),
  createUser('Mike'),
  createUser('Emma', undefined, false),
  createUser(null, 30)
];

console.log(users.map(u => `${u.name}-${u.age}-${u.active}`).join('|'));