OptionaladditionalOptionaladvanceMark this line as an advance (előleg) charge (advanceData).
true reports the advance itself — a line of an advance invoice
(előlegszámla). NAV's advance-invoice lines carry only the net amount and
the VAT rate; the builder omits lineVatData/lineGrossAmountData for
these lines (the summary still derives the VAT from the rate).OptionalexchangeRate?: string | numberExchange rate applied to the advance. Defaults to the invoice rate.
Number of the advance invoice that reported the payment.
Date the advance was paid, yyyy-mm-dd.
OptionalnatureDefaults to PRODUCT.
OptionalunitUnit of measure. Defaults to PIECE.
Net unit price, in the invoice currency.
VAT rate as a fraction, e.g. 0.27.
Conventionally named extra data for this line (
additionalLineData). NAV has no free-text line note; a "Tétel megjegyzés" must be a structured field whosedataNamefollows NAV's[A-Z][0-9]{5}_...convention. Validated byvalidateInvoice.