What does this WeakMap lookup print?

What does this WeakMap lookup print?

const roles = new WeakMap();
const session = { id: 'S-1' };
roles.set(session, 'admin');

console.log(roles.get({ id: 'S-1' }));
console.log(roles.get(session));

1. undefined, then admin
2. admin, then admin
3. undefined, then undefined
4. It throws because WeakMap cannot store objects.