I am using the xero-node SDK.
I use the getInvoices entry point, and everything works fine meaning that the Invoice data is correct. The Contact JSON object is also returned with the Invoice data (which surprised me) which contains the Contact associated with this invoice.
However, Contact data is blank other than the ContactID and the Contact name. Why would the API return a blank object? This means I have to make an extra call to get the 'real' Contact data. Doesn't make sense.