I'm trying to update the personal data and billing address fields

I’m trying to update the cart details using : JavaScript SDK API – Snipcart Documentation.
But I get this weird error in catch block without any message key. The whole object looks like → “Object { kind: Getter & Setter, form: Getter & Setter, fields: Getter & Setter, … }”. I am passing all mandatory fields in update method. When I’m trying to update just the email it works.

You might partially updating the billing/shipping address or one of address fields failed to pass.

How can i see which fields I’m passing are incorrect?

I saw someone modifying the snipcart script and self hosting it.

I can’t really say without checking the actual site.