riot-starter/docs/modules.md

Module System

ES6 Modules just dont work well inside RiotJS tags (<=3), you could include them at the top of the page, but that requries a build-watch-proccess that goes against -- a zero-build develop process!

Mixins is Riots answer to shared / resultable componet logic, but you want an easy way to compose larger bits of logic before they were injected into riot.mixin, that is why the build process (gulp) treats javascript files differently.

While using ES Modules for application logic, tags need to be built separately.

• Tags are build with Riot, and minified
• Application JS is built with Rollup, and minified (iife format)