BR-DEC-01 — E-Invoice Validation Rule & Fix

Fixture ID: allowanceOverPrecise · XPath: /ubl:Invoice/cac:AllowanceCharge[1]/cbc:Amount

1. Why This Rule Triggers (Diagnostic Message)

The allowed maximum number of decimals for the document level allowance amount (BT-92) is 2, but allowances[0].amount is 10.005, which has 3. The schematron measures the digits after the decimal point in the serialised XML, so a value that merely *displays* as two decimals still fails when the underlying number carries more. An allowance amount usually arrives as a percentage of something — 3% settlement discount, 1.5% surcharge — and a percentage of a two-decimal figure is almost never a two-decimal figure. EN 16931 wants the *result* rounded, once, before it is written.

2. How to Fix BR-DEC-01

Round allowances[0].amount to two decimals before you hand it over — 10.01 here. This package exports round2() for it, which avoids the two JavaScript traps: Math.round(1.005 * 100) / 100 gives 1.00, and (2.675).toFixed(2) gives "2.67".

3. Valid Code / Payload Example

"amount": 10.01