Sample
Configure @babel/preset-env to selectively downlevel modern ECMAScript features based on target runtimes while supporting forceAllTransforms, plugin includes/excludes, and module formats.
sha256:352d76efd66b3e81907c305dd7b210b6b11f2bf5e9191cd5e1f56b8334d9ffa9
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
- Configure @babel/preset-env to selectively downlevel modern ECMAScript features based on target runtimes while supporting forceAllTransforms, plugin includes/excludes, and module formats. HOW
- Packages
-
@babel/preset-env 8.0.2
- Environment
- node
- Created
- 2026-08-17T06:39:21Z
Contract
- @babel/preset-env selectively downlevels modern ECMAScript syntax such as private fields, static initialization blocks, and optional chaining only when missing in the declared runtime targets, while preserving native syntax on modern engines.
- Targeting Node 22 leaves private fields, static blocks, optional chaining, nullish coalescing, and logical assignment operators as native syntax without helper functions.
- Targeting Node 12 downlevels private class fields to WeakMap instances and optional chaining to nullish checks, while preserving native ES6 classes and arrow functions.
- Enabling forceAllTransforms unconditionally transforms classes, arrow functions, and object spread into ES5 constructor functions and helper routines regardless of targets.
- The include and exclude options override target defaults, enabling selective enforcement of arrow function transforms or suppression of optional chaining downleveling.
- The modules option controls module emission, preserving ESM import/export statements when false and generating CommonJS exports and helpers when set to 'commonjs'.
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- 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