In JavaScript, how can I conditionally assign value to object with destructuring and short circuit evaluation?

Let’s say I have this set up:

const objA = { name: "Jacob", email: "jacob@email.com" };
const objB = { lastName: "Smith" };

Why can I do this:

const lastName = objA.lastName || objB.lastName;

But not this?

const { lastName } = objA || objB;

Was able to re-create above example in dev tools.

My real world application: I have "normal" and "legacy" account roles, and after querying both types of roles, I’d like to be able to do:

const { schoolAdmin } = account || legacyAccount;

… but instead have to do:

const schoolAdmin = account.schoolAdmin || legacyAccount.schoolAdmin;

Which is admittedly not a big deal, but I feel like there’s something I’m missing and that I could use destructuring here. Jr dev, sorry if this is a dummy question!
(Sometimes there is no account, and sometimes there is an account that doesn’t have the schoolAdmin role! Likewise with legacyAccount.)

>Solution :

As explained in the comments || doesn’t evaluate to union of objects, it returns the second one

You can do this instead:

const { lastName } = { ...objA, ...objB };

It does create a union