toJson method
Converts the card details to a map for native bridge communication.
Implementation
Map<String, dynamic> toJson() {
return {
'cardholderName': cardholderName,
'cardNumber': cardNumber,
'expirationMonth': expirationMonth,
'expirationYear': expirationYear,
'securityCode': securityCode,
if (billingAddress != null) 'billingAddress': billingAddress,
};
}