Going to cut a first experimental release of this, so making some helper tools before I do. Primarily, want to make sure that we get the .flow file in the published package — otherwise the entire purpose of the package is defeated — so that means baking it into the npm run build process.
npm run build
Extract `cp` function into `utils` module
I'm about to re-use this functionality in another build task, so
extracting it here.
utils: add `exec` and `print` convenience functions
types: Add build-js script and package.json script
- build-js: builds base JS file(s) and package.json.
- build-flow: builds auxiliary Flow file(s).
- build: does both ("build-flow" is fast enough that we can do it
whenever we build).