Credit card form with validation and linked fields

Build a card-details form in the browser (React is fine): cardholder name, card number, expiry date and security code. Validate each field as the user types and on submit, and show errors next to the field. The fields depend on each other: what the user enters in one changes how another behaves or is checked, so the related fields must revalidate when it changes. Explain how you hold the form state and keep the dependent checks in one place.