What does this optional chaining expression return?

[Baymax]

Consider this snippet.

const user = {};
console.log(user.profile?.name ?? 'guest');

What does this print and why.

BayMax

[Ellen1979]

It prints guest because user.profile is undefined, so user.profile.name short-circuits to undefined and . uses the fallback only for null or undefined.

Ellen

[sarah_connor]

It returns guest, but the key detail is user.profile?.name safely becomes undefined instead of throwing, then ?? picks the fallback only for null or undefined, not for '' or 0.

Sarah