• Node.js ^20, ^22, or ^24
• npm

npm ci

1. Create a branch from main.
2. Make the smallest coherent change that solves the problem.
3. Add or update runtime tests, type tests, and documentation as needed.
4. Run the verification commands before opening a pull request.
5. Add a changeset if the published package behavior changes.

Run the full local gate:

npm run verify

Run coverage separately when needed:

npm run test:coverage

Useful focused commands:

npm run lint
npm run typecheck
npm test
npm run build
npm run test:package
npm run bench
npm run publish:package

• Add positive and negative behavioral coverage for runtime guards.
• Keep type-level narrowing coverage current in src/__tests__/narrowing.types.ts.
• Preserve the per-file coverage threshold enforced by the repository scripts.
• Keep consumer smoke tests passing for both CommonJS and ESM package usage.

Create a changeset whenever a pull request changes the published package in a way that should produce a version bump or release note entry.

npm run changeset

Changesets are applied during release with:

npm run release:version

Changesets can be published with:

npm run release:changesets

The GitHub release workflow publishes with npm provenance enabled. The local npm run publish:package command does not force provenance, because npm only supports automatic provenance generation in supported CI providers.

• The package publishes built files from dist/.
• The root README.md, LICENSE, and package.json are included in the npm tarball automatically.
• Source maps are intentionally not published.

• Keep pull requests focused.
• Update documentation when behavior, packaging, or workflow changes.
• Do not relax quality gates to make a change pass. Fix the code, tests, or tooling instead.