fix(sv/nit): align check digit logic with Python reference implementa…#155
fix(sv/nit): align check digit logic with Python reference implementa…#155menyinch wants to merge 3 commits into
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The TypeScript NIT validator diverged from the upstream python-stdnum
implementation in two places, causing valid NITs to be rejected.
1. Old-vs-new NIT branch selection
The condition used strict equality against the sequential block:
value.substr(10, 3) === '100'
The Python reference uses a lexicographic comparison:
number[10:13] <= '100'
As a result, any "old" NIT whose sequential block was below '100'
(i.e. '000'–'099') was being validated with the new-NIT formula and
incorrectly flagged as InvalidChecksum. Changed to `<= '100'` to
match.
2. New-NIT check digit edge case
The formula was:
(11 - weightedSum(...)) % 10
The Python equivalent is:
(-total % 11) % 10
which, expanded, is `((11 - total % 11) % 11) % 10`. The outer `% 11`
matters: when the weighted sum is divisible by 11, Python returns 0
while the TS version returned 1, rejecting otherwise-valid numbers.
Added the missing `% 11` step.
No changes to weights, length/format/component checks, or the SV-prefix
handling. Verified against the docstring fixture `0614-050707-104-8`.
Summary of ChangesHello, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request addresses discrepancies between the TypeScript NIT validator and the upstream python-stdnum reference implementation. By correcting the branch selection logic and the checksum calculation formula, the changes ensure that valid NITs are no longer incorrectly rejected. Highlights
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Code Review
This pull request updates the NIT validation logic in src/sv/nit.ts by expanding the condition for the first sum calculation and refining the check digit calculation with an additional modulo operation. Feedback suggests replacing the deprecated substr() method with slice() for better standards compliance and correcting minor spacing inconsistencies in the mathematical expressions.
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
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The TypeScript NIT validator diverged from the upstream python-stdnum implementation in two places, causing valid NITs to be rejected.
Old-vs-new NIT branch selection
The condition used strict equality against the sequential block:
The Python reference uses a lexicographic comparison:
As a result, any "old" NIT whose sequential block was below '100' (i.e. '000'–'099') was being validated with the new-NIT formula and incorrectly flagged as InvalidChecksum. Changed to
<= '100'to match.New-NIT check digit edge case
The formula was:
The Python equivalent is:
which, expanded, is
((11 - total % 11) % 11) % 10. The outer% 11matters: when the weighted sum is divisible by 11, Python returns 0 while the TS version returned 1, rejecting otherwise-valid numbers. Added the missing% 11step.No changes to weights, length/format/component checks, or the SV-prefix handling. Verified against the docstring fixture
0614-050707-104-8.