Joyee Cheung 0b9249e335 module: implement the "module-sync" exports condition ... This patch implements a "module-sync" exports condition for packages to supply a sycnrhonous ES module to the Node.js module loader, no matter it's being required or imported. This is similar to the "module" condition that bundlers have been using to support `require(esm)` in Node.js, and allows dual-package authors to opt into ESM-first only newer versions of Node.js that supports require(esm) while avoiding the dual-package hazard. ```json { "type": "module", "exports": { "node": { // On new version of Node.js, both require() and import get // the ESM version "module-sync": "./index.js", // On older version of Node.js, where "module" and // require(esm) are not supported, use the transpiled CJS version // to avoid dual-package hazard. Library authors can decide // to drop support for older versions of Node.js when they think // it's time. "default": "./dist/index.cjs" }, // On any other environment, use the ESM version. "default": "./index.js" } } ``` We end up implementing a condition with a different name instead of reusing "module", because existing code in the ecosystem using the "module" condition sometimes also expect the module resolution for these ESM files to work in CJS style, which is supported by bundlers, but the native Node.js loader has intentionally made ESM resolution different from CJS resolution (e.g. forbidding `import './noext'` or `import './directory'`), so it would be semver-major to implement a `"module"` condition without implementing the forbidden ESM resolution rules. For now, this just implments a new condition as semver-minor so it can be backported to older LTS. Refs: https://webpack.js.org/guides/package-exports/#target-environment-independent-packages PR-URL: https://github.com/nodejs/node/pull/54648 Fixes: https://github.com/nodejs/node/issues/52173 Refs: https://github.com/joyeecheung/test-module-condition Refs: https://github.com/nodejs/node/issues/52697 Reviewed-By: Jacob Smith <jacob@frende.me> Reviewed-By: Jan Krems <jan.krems@gmail.com> Reviewed-By: Chengzhong Wu <legendecas@gmail.com>		2024-09-25 06:35:26 +00:00
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node_modules
dynamic_import.js
import.mjs
require.cjs