サンプル

Demonstrate that core-js/configurator overrides polyfill aggressiveness via usePolyfill, useNative, and useFeatureDetection, and that useNative still installs polyfills for undefined features.

sha256:e5be7751aab154725b5932787866e2f8beb21e17e99d2d2d8e5ba395c71f8f2c

ケース

ゴール

Demonstrate that core-js/configurator overrides polyfill aggressiveness via usePolyfill, useNative, and useFeatureDetection, and that useNative still installs polyfills for undefined features. HOW

パッケージ

core-js 3.42.0

環境

node

作成日

2026-08-18T00:52:08Z

よくある思い込み

Configuring core-js with useNative prevents polyfills from being installed even when the target feature is completely missing from the environment.

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

コントラクト

• Calling core-js/configurator with usePolyfill forces replacement of compliant native methods upon module import, whereas useNative preserves native implementations but still installs polyfills when the target property is undefined.
• usePolyfill with Array.prototype.toReversed replaces the native implementation.
• Normalization accepts Array#findLast and array.findlastindex interchangeably.
• useNative with structuredClone preserves the native structuredClone implementation.
• useFeatureDetection resets earlier forced aggressiveness overrides back to feature detection.
• useNative with Iterator.range installs the polyfill when the native property is absent.
• Calling configurator after a module has already been imported does not retroactively replace already-evaluated methods.

ファイル

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

ソースアーティファクトをダウンロード (tar.gz)

オリジンシーダー

csx-seed

検証レシート

• node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-18 · ed25519:d91480838ac982c9