[alexander-akait]

Summary

schema-utils precompile writes a CommonJS module. In a package with "type": "module", Node.js loads options.check.js as an ES module, so module.exports throws. That blocks less-loader, sass-loader and stylus-loader from using a precompiled check.

• CLI: the check is an ES module when the nearest package.json has "type": "module", the way Node.js reads a .js file there. Otherwise it stays CommonJS. A package.json that can't be parsed counts as CommonJS.
• API: precompile(schema, { esm: true }).
• Runtime helpers: ajv keeps require for its helpers even in ES module output. These are imported once with import schemaUtilsRuntime from "schema-utils/dist/runtime.js", and only when the check uses one. The .js extension is needed because schema-utils has no exports field, and Node.js won't resolve the path in an ES module without it.
• No change to CommonJS output. Regenerating minimizer-webpack-plugin's check gives a byte-identical file.

Tests

• The generated ES module imports the runtime and has no require or module.exports. When no helper is used, there's no import.
• A check is written next to a "type": "module" package.json, symlinked to this package, and imported by a real Node.js process. This runs on Node.js 14+. It caught the missing .js extension, which would have broken every ES module check that uses a helper.
• The CLI writes an ES module under "type": "module", CommonJS under "type": "commonjs" in the same run, and CommonJS when package.json can't be read.
• I generated less-loader's real schema as an ES module and imported it natively. It accepts valid options and rejects invalid ones.

npm run lint and the full suite (1038 tests) pass. Coverage is 100% statements in cli.js and 98.9% in precompile.js.

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Generated by Claude Code

Summary by CodeRabbit

• New Features
  • Generated schema checks can now use ES modules. The precompile API offers an esm option to select the output format; without it, output remains CommonJS.
  • The CLI automatically generates ES modules when the nearest package.json sets "type": "module"; otherwise, it generates CommonJS, including when the package configuration is missing or invalid.
• Documentation
  • Updated precompilation documentation to describe the output formats and the new esm option.

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ℹ️ Recent review info

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Reviewing files that changed from the base of the PR and between 919e95d and e376425.

📒 Files selected for processing: 1

• src/cli.js

🚧 Files skipped from review as they are similar to previous changes: 1

• src/cli.js

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Walkthrough

precompile now supports ES module output through an optional esm setting. The CLI selects the output format from the nearest package.json. Tests cover generated ES module output, validator execution, and CLI behavior for module, CommonJS, and malformed package files.

Priority: ➖ Normal

Merge Risk: ⚪ Minimal · up to e3764

No actionable merge-blocking issue is established; the change is mergeable after normal checks.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: adding ES module output for precompiled schemas in packages with "type": "module".
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 4 files.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: Organization UI
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• Run ID: 03dda01a-a489-41b9-a5ef-ae26e667c820

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Reviewing files that changed from the base of the PR and between a6e125a and 919e95d.

📒 Files selected for processing: 6

• .changeset/precompile-esm.md
• README.md
• declarations/precompile.d.ts
• src/cli.js
• src/precompile.js
• test/precompile.test.js

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.17%. Comparing base (a6e125a) to head (e376425).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #233      +/-   ##
==========================================
+ Coverage   97.11%   97.17%   +0.05%     
==========================================
  Files          13       13              
  Lines        1180     1204      +24     
  Branches      458      466       +8     
==========================================
+ Hits         1146     1170      +24     
  Misses         32       32              
  Partials        2        2              

Flag	Coverage Δ
integration	97.17% <100.00%> (+0.05%)	⬆️

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