Sample
prove that transpiling a named capture group regex mutates its serialization shape by stripping the named groups from its .source property, even though evaluation semantics are preserved
sha256:15dd17f193ef111f72ee349d6af1c3b8051e9157c5ba59126ce65b3d88afd6d1
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Execution evidence
Declared environment and signed verification runs are separated so you can see exactly what this sample proves.
Evidence basisSigned contract pass
Verification receipts1
Verification levelL3_CONTRACT_PASS
Declared environment
- Execution context
- node
- Operating system
- linux
- Architecture
- x64
- Runtime
- node
- Language
- node
- Package manager
- npm
Verification-run environments
- Execution context
- node 22
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- node 22
- Language
- javascript
- Package manager
- npm
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17
Case
- Goal
- prove that transpiling a named capture group regex mutates its serialization shape by stripping the named groups from its .source property, even though evaluation semantics are preserved HOW
- Packages
-
@babel/preset-env 7.29.7
- Environment
- node
- Created
- 2026-08-17T06:38:36Z
Commonly assumed
a regular expression with named capture groups compiled by Babel will preserve the exact syntactic shape of the pattern in its .source property
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- the .source property of a named capture group regex transpiled for IE11 evaluates to a string stripped of the capture group names, rather than the original source string
- assert.strictEqual(nativeRegex.source, '(?<year>\\d{4})-(?<month>\\d{2})-(?<day>\\d{2})');
- assert.strictEqual(transpiledRegex.source, '(\\d{4})-(\\d{2})-(\\d{2})');
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- test.mjs
- test/contract.mjs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17 · ed25519:d91480838ac982c9