샘플

Demonstrate that @babel/preset-env defaults useBuiltIns to false, performing syntax-only transpilation without polyfilling missing built-in APIs unless explicitly configured.

sha256:8f91486f2c59f67a07afd45b8a3a5988da85d7f85f7f3347a1c43d8e1c5c1a31

케이스

목표

Demonstrate that @babel/preset-env defaults useBuiltIns to false, performing syntax-only transpilation without polyfilling missing built-in APIs unless explicitly configured. HOW

패키지

@babel/preset-env 7.29.7 @babel/core 7.29.7 core-js 3.50.0

환경

node

생성일

2026-08-16T15:46:58Z

흔히 이렇게 알고 있다

Leaving useBuiltIns unset in @babel/preset-env automatically injects polyfills for unsupported ECMAScript standard library methods across configured target environments when corejs is configured or core-js is imported.

이 샘플의 작성자가 여기서 개발자나 모델이 기대할 법한 내용으로 적어둔 것이다. 아래 계약이 실제로 실행된 것이다.

컨트랙트

• When useBuiltIns is unset, @babel/preset-env defaults to false and leaves standard library methods un-polyfilled without injecting any core-js imports, even when targets lack support or corejs is specified.
• assert leaving useBuiltIns unset leaves built-in methods like Array.prototype.flat, Object.fromEntries, and Promise.allSettled completely un-polyfilled without core-js module imports
• assert specifying corejs alone without enabling useBuiltIns has no effect on polyfill injection
• assert leaving useBuiltIns unset preserves raw core-js entry imports rather than splitting them into per-target polyfill imports
• assert useBuiltIns: 'usage' with corejs scans AST usage and injects only the required core-js module imports
• assert useBuiltIns: 'entry' with corejs replaces monolithic core-js imports with target-specific individual polyfill imports

파일

• NOTES.md
• csx.json
• package-lock.json
• package.json
• test/contract.mjs

검증된 아티팩트 내려받기 (tar.gz) — 컨트랙트가 실제로 실행된 바로 그 바이트

오리진 시더

csx-seed

검증 영수증

• node 22 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-16 · ed25519:d91480838ac982c9