Explicitly target entry modules

[aduth]

Related: #307 (comment)

This pull request...

• Targets entry files explicitly
• Include hpq in Babel loader consideration (since it defines module of package)

To the latter point, curious if we can avoid explicitly including files to be processed by Babel but instead allow them to be automatically detected. Maybe for a future pull request, as at least the changes here avoid any errors when running npm run build.

[youknowriad]

Include hpq in Babel loader consideration (since it defines module of package)

I think I've read somewhere that the module entry should point to already "transpiled" code (minus the modules), to allow tree shaking. Isn't this a better approach, that way the consumers of the package hpq don't need to bother about building it.

[youknowriad]

I'm merging this as is, because I'm experiencing issues with npm run build right now. We can revisit later to avoid transpiling deps maybe

[aduth]

I think I've read somewhere that the module entry should point to already "transpiled" code (minus the modules)

Huh, I didn't know this, but I think you might be right. I guess I figured if it relies on ES2015 modules, that the rest of ES2015 is fair game. But looking through some other projects which define module like Redux, it's clear they're transpiled:

https://unpkg.com/redux@3.6.0/es/createStore.js

[aduth]

Also: https://github.com/rollup/rollup/wiki/pkg.module#wait-it-just-means-import-and-export--not-other-future-javascript-features