refactor: extract alphabetToNumber helper, optimize SSN blacklist lookup#157
refactor: extract alphabetToNumber helper, optimize SSN blacklist lookup#157Wolfvin wants to merge 1 commit into
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Changes: 1. src/util/checksum.ts: - Extract alphabetToNumber() helper from mod97base10Validate() - Uses early-return pattern instead of mutable fail flag - Cleaner iteration with for-of instead of split+map+join 2. src/us/ssn.ts: - Convert invalidSSN array to invalidSSNSet (Set) for O(1) lookup - Remove duplicate '999999999' entry from the blacklist - Change invalidSSN.includes() to invalidSSNSet.has() Both changes are behavior-preserving — verified by: - Full test suite: 1605 tests passing - Regrets regression: 7 clusters all GREEN - Raw output comparison: identical to pre-refactor truth - Fingerprint cross-match: all fingerprints match Note: luhnChecksumValidate was NOT refactored to delegate to luhnChecksum because they compute the Luhn algorithm differently (one reverses, one doesn't). Attempting this change broke 6 test suites, demonstrating the value of output-based regression testing.
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 introduces two performance and structural improvements. The changes focus on optimizing lookup operations for SSN validation and centralizing character conversion logic to reduce code duplication, all while maintaining existing behavior verified through regression testing. Highlights
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Code Review
This pull request optimizes SSN validation by converting the invalidSSN array into a Set for faster lookups and refactors the checksum utility by extracting a reusable alphabetToNumber helper function. Feedback suggests exporting the alphabetToNumber helper so it can be reused across other modules, and removing the remaining '999999999' entry from the SSN blacklist since it is already covered by an existing regex check.
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| '888888888', | ||
| '999999999', | ||
| '123123123', | ||
| '999999999', |
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While removing the duplicate '999999999' is a good cleanup, the remaining '999999999' entry (now on line 28) is also completely redundant. Any SSN starting with 9 (including 999999999) is already rejected by the regex check /^(000|666|9)\d+/ on line 99. Therefore, both entries can be safely removed from the blacklist.
| function alphabetToNumber( | ||
| value: string, | ||
| alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', | ||
| ): string | null { |
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Since the PR description mentions that this helper is intended to be reused by other functions/modules that need alphanumeric-to-numeric conversion, it should be exported so that other files can import it.
| function alphabetToNumber( | |
| value: string, | |
| alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', | |
| ): string | null { | |
| export function alphabetToNumber( | |
| value: string, | |
| alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', | |
| ): string | null { |
| import { Validator, ValidateReturn } from '../types'; | ||
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| const invalidSSN = [ | ||
| const invalidSSNSet = new Set([ |
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I will note that if this is a performance optimization, that object keys are the fastest with a if (value in invalidSSN) { as the check will out perform Set().
| * Convert a string using alphanumeric alphabet to its numeric representation. | ||
| * Returns null if any character is not in the alphabet. | ||
| */ | ||
| function alphabetToNumber( |
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Summary
Two small, behavior-preserving refactors verified with output-based regression testing (using the Regrets skill).
Changes
1.
src/util/checksum.ts— ExtractalphabetToNumber()helpermod97base10Validate()into a dedicatedalphabetToNumber()functionfailflagfor-ofinstead ofsplit().map().join()2.
src/us/ssn.ts— Optimize blacklist lookupinvalidSSNarray toinvalidSSNSet(aSet) for O(1) lookup instead of O(n)999999999entry from the blacklistinvalidSSN.includes(value)toinvalidSSNSet.has(value)Verification
All changes verified with 3 independent methods:
Regrets Clusters Tested
us-ssn-validate— US SSN validationid-npwp-validate— Indonesian NPWP validationbr-cpf-validate— Brazilian CPF validationgb-nino-validate— UK NINO validationchecksum-luhn— Luhn checksumchecksum-mod97— ISO 7064 Mod 97,10checksum-mod11mod10— ISO 7064 Mod 11,10Key Finding
I initially attempted to refactor
luhnChecksumValidate()to delegate toluhnChecksum()(DRY principle). However, these two functions compute the Luhn algorithm differently —luhnChecksumreverses the string before processing whileluhnChecksumValidateprocesses left-to-right. The refactoring broke 6 test suites immediately. This demonstrates the value of output-based regression testing for catching subtle behavioral differences.I did NOT include this change since it alters behavior.