Design package scripts

Before choosing a tool or writing more code, make the requirement concrete. The same npm test and npm run build commands work locally, in CI, and just before publishing.

Scripts are the package interface for maintainers and CI; they should describe outcomes and compose predictably. The useful target is not encyclopedic coverage. Make one deliberate choice, observe its consequences, and know which requirement would make you revise it.

A common failure is to hide essential setup in an undocumented personal shell command. The happy path may still work, which makes the mistake easy to miss. create a small script vocabulary, keep platform-specific shell tricks out, and make failures stop the pipeline. Keep the first version small enough that every important input and output remains visible.

This supports the module goal: Develop the package against a real consumer and make build and test behavior reproducible from a clean checkout. Capture the request, command, trace, screenshot, test result, or other evidence that proves the result.

Delete generated output, install cleanly, and run the documented scripts in the order a new maintainer would. Change one condition on purpose, predict the result, and compare the prediction with what actually happened.