What does this program print?

What does this program print?

const key = {};
const cache = new WeakMap([[key, undefined]]);

console.log(cache.has(key), cache.get(key));
console.log(cache.has({}), cache.get({}));

1. true undefined false undefined
2. false undefined false undefined
3. true null true null
4. It throws because WeakMap cannot store undefined.