CodeSampleX

Sample

@babel/plugin-transform-duplicate-named-capturing-groups-regex 7.29.7: pluginTransformDuplicateNamedCapturingGroupsRegex

Verified sample for npm @babel/plugin-transform-duplicate-named-capturing-groups-regex 7.29.7: pluginTransformDuplicateNamedCapturingGroupsRegex. The…

sha256:4ada05512b46045d56a1726edb6373b1d3dc78e60e5b92209b291eb2b44c78fd

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment node linux 24 · ubuntu · glibc 2.39 x64 node node npm

Verification-run environments

Environment Contract Stages Run
node 22 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22-alpine@sha256:c610fcdfb1d5…		 2026-08-26

Case

HOW
Goal
verify pluginTransformDuplicateNamedCapturingGroupsRegex in pkg:npm/%40babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7
Packages
Symbols
  • pluginTransformDuplicateNamedCapturingGroupsRegex
Environment
node
Created
2026-08-26T04:41:54Z

Contract

  1. pluginTransformDuplicateNamedCapturingGroupsRegex exports a valid Babel plugin function
  2. @babel/plugin-transform-duplicate-named-capturing-groups-regex compiles duplicate named capturing groups across disjunction branches into wrapped regex helper
  3. transformed regex resolves match.groups.<name> for the first branch (YYYY-MM)
  4. transformed regex resolves match.groups.<name> for the second branch (MM-YYYY)
  5. transformed regex returns null when input does not match
  6. String.prototype.replace substitutes $<name> group references correctly using the transformed regex

Files

  • NOTES.md
  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • src/index.mjs
  • test/contract.mjs

Download the source artifact (tar.gz)

Source

NOTES.md
# Babel Plugin: `@babel/plugin-transform-duplicate-named-capturing-groups-regex`

## Prior Solutions Search

An initial search of known solutions for `@babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7` with symbol `pluginTransformDuplicateNamedCapturingGroupsRegex` returned `NO_SAFE_MATCH`.

## Pinned Release

- `@babel/plugin-transform-duplicate-named-capturing-groups-regex`: `7.29.7`
- `@babel/core`: `^7.26.0`
- Runtime: Node.js (`>=18`, tested on Node 22+)

## Observed Behaviour

1. **Symbol and Plugin Structure**:
   - `pluginTransformDuplicateNamedCapturingGroupsRegex` exports a Babel plugin generator function (accessible as default export or interop wrapper) that attaches AST visitor passes for RegExp literals with duplicate named capturing groups across disjunction branches.

2. **Regex Compilation with Disjunction Named Captures**:
   - In ECMAScript regex patterns containing duplicate capture group names in separate disjunction branches (e.g. `/(?<year>\d{4})-\d{2}|\d{2}-(?<year>\d{4})/`), the plugin transforms the regex literal into indexed capturing groups wrapped by a runtime RegExp helper (`_wrapRegExp`).

3. **Unified Named Group Resolution at Runtime**:
   - Executing `.exec(input)` on the transformed RegExp instance resolves `result.groups.<name>` correctly regardless of which disjunction branch was matched.
   - For non-matching inputs, `.exec(input)` returns `null`.

4. **String Replacement Compatibility**:
   - `String.prototype.replace(regex, "Year: $<year>")` correctly substitutes named replacement tokens using the mapped capture indices.

## Failure Mode

Engines and runtimes without native support for RegExp duplicate named capturing groups throw a syntax error (`SyntaxError: Invalid regular expression: Duplicate capture group name`). Applying `pluginTransformDuplicateNamedCapturingGroupsRegex` during Babel compilation resolves the syntax error and ensures consistent group extraction across all branches.
PROMPT.md
Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pluginTransformDuplicateNamedCapturingGroupsRegex in pkg:npm/%40babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7
Demonstrate these symbols/APIs:
  - pluginTransformDuplicateNamedCapturingGroupsRegex

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.
csx.json
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package-lock.json
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package.json
{
  "name": "csx-sample-babel-plugin-duplicate-named-groups",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@babel/core": "^7.26.0",
    "@babel/plugin-transform-duplicate-named-capturing-groups-regex": "7.29.7"
  }
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pluginTransformDuplicateNamedCapturingGroupsRegex in pkg:npm/%40babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40babel/plugin-transform-duplicate-named-capturing-groups-regex@7.29.7"
  ],
  "symbols": [
    "pluginTransformDuplicateNamedCapturingGroupsRegex"
  ]
}
src/index.mjs
import babel from '@babel/core';
import pluginTransformDuplicateNamedCapturingGroupsRegex from '@babel/plugin-transform-duplicate-named-capturing-groups-regex';

export { pluginTransformDuplicateNamedCapturingGroupsRegex };

/**
 * Transforms JavaScript code containing regular expressions with duplicate named capturing groups
 * in disjunction branches (e.g. `/(?<year>\d{4})-\d{2}|\d{2}-(?<year>\d{4})/`) into backward-compatible
 * regular expressions using @babel/plugin-transform-duplicate-named-capturing-groups-regex.
 *
 * @param {string} code - JavaScript source code to transform.
 * @param {object} [options] - Additional Babel options.
 * @returns {string} - Transformed code with regex wrappers.
 */
export function transformDuplicateNamedGroups(code, options = {}) {
  const result = babel.transformSync(code, {
    plugins: [pluginTransformDuplicateNamedCapturingGroupsRegex],
    configFile: false,
    babelrc: false,
    ...options,
  });
  return result ? result.code : '';
}

/**
 * Compiles a regular expression pattern containing duplicate named capturing groups
 * into an executable runtime RegExp using the Babel transform plugin.
 *
 * @param {string} pattern - Regular expression pattern string.
 * @param {string} [flags=''] - Regular expression flags.
 * @returns {Promise<RegExp>} - Executable wrapped RegExp instance.
 */
export async function createTransformedRegExp(pattern, flags = '') {
  const code = `export default /${pattern}/${flags};`;
  const transformed = transformDuplicateNamedGroups(code);
  const moduleUrl = 'data:text/javascript;charset=utf-8,' + encodeURIComponent(transformed);
  const mod = await import(moduleUrl);
  return mod.default;
}
test/contract.mjs
import { strict as assert } from 'node:assert';
import {
  pluginTransformDuplicateNamedCapturingGroupsRegex,
  transformDuplicateNamedGroups,
  createTransformedRegExp,
} from '../src/index.mjs';

// 1. Verify pluginTransformDuplicateNamedCapturingGroupsRegex export structure
assert(pluginTransformDuplicateNamedCapturingGroupsRegex !== null && typeof pluginTransformDuplicateNamedCapturingGroupsRegex === 'object');
const pluginFn = pluginTransformDuplicateNamedCapturingGroupsRegex.default || pluginTransformDuplicateNamedCapturingGroupsRegex;
assert.equal(typeof pluginFn, 'function');

// 2. Verify compilation of regex with duplicate named capturing groups in disjunctions
const sourceCode = `
export function parseDate(input) {
  const re = /(?<year>\\d{4})-\\d{2}|\\d{2}-(?<year>\\d{4})/;
  return re.exec(input);
}
`;

const transformedCode = transformDuplicateNamedGroups(sourceCode);
assert(transformedCode.includes('_wrapRegExp') || transformedCode.includes('BabelRegExp'), 'Transformed code should contain regexp wrapper');

// 3. Verify runtime execution of matched duplicate named groups for branch 1 (YYYY-MM)
const moduleUrl = 'data:text/javascript;charset=utf-8,' + encodeURIComponent(transformedCode);
const mod = await import(moduleUrl);

const matchBranch1 = mod.parseDate('2026-08');
assert(matchBranch1 !== null, 'Branch 1 should match');
assert.equal(matchBranch1.groups.year, '2026');

// 4. Verify runtime execution of matched duplicate named groups for branch 2 (MM-YYYY)
const matchBranch2 = mod.parseDate('08-2026');
assert(matchBranch2 !== null, 'Branch 2 should match');
assert.equal(matchBranch2.groups.year, '2026');

// 5. Verify non-matching input returns null
const noMatch = mod.parseDate('invalid-input');
assert.equal(noMatch, null);

// 6. Verify String.prototype.replace with named capturing group substitution
const regex = await createTransformedRegExp('(?<year>\\d{4})-\\d{2}|\\d{2}-(?<year>\\d{4})');
assert.equal('2026-08'.replace(regex, 'Year: $<year>'), 'Year: 2026');
assert.equal('08-2026'.replace(regex, 'Year: $<year>'), 'Year: 2026');

console.log('CONTRACT PASS: pluginTransformDuplicateNamedCapturingGroupsRegex verified');

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