[gyanu2507]

Decimals that round to a whole number serialize to a string that ends in a period:

serializeItem(1.0001);  // '1.'
serializeItem(9.9999);  // '10.'
serializeItem(-0.0001); // '-0.'

That isn't a valid Decimal, and this library's own parser rejects it:

parseItem(serializeItem(1.0001));
// ParseError: Parse error: Decimal cannot end on a period at offset 2

RFC 9651 section 4.1.5 (same as RFC 8941) says "If input_decimal's fractional component is zero, append '0' to output", so the expected values are 1.0, 10.0 and -0.0.

serializeDecimal rounds with toFixed(3) and then strips trailing zeros with replace(/0+$/, ''). When all three fractional digits are zero, that also leaves nothing after the period. The fix appends a 0 in that case. Everything else in serializeDecimal is unchanged, including the 12-digit check, which already runs on the rounded value.

The httpwg tests don't catch this because their serialization inputs that round to a whole number are integers in JavaScript.

Testing

Added a case to the serializeItem tests in test/serializer-tests.js that serializes 1.0001, 9.9999 and -0.0001, checks the output, and parses it back.

• make test (lint, build, httpwg tests and the serializer tests): 2823 pass, 0 fail.
• Without the change in src/serializer.ts, the new test fails and everything else passes.

I also added a changelog entry under an unreleased 2.1.1 heading. Happy to change or drop that if you'd rather write it yourself.

[evert]

Dang, thank you!