isDiscountAmountValid function
Implementation
bool isDiscountAmountValid(MatexVatCalculatorState state) {
if (state.priceBeforeVat != null) {
return state.discountAmount == null ||
(state.discountAmount! < state.priceBeforeVat! &&
state.discountAmount! >= 0);
} else if (state.priceAfterVat != null) {
return state.discountAmount == null ||
(state.discountAmount! < state.priceAfterVat! &&
state.discountAmount! >= 0);
}
return false;
}