A very simple micro-frontends implementation in vanilla javascript. The main
container app is server-side rendered (using express) so that the location of
the "sub" apps can be specified with an env var (using a .env file).
The included sub apps are included via a javascript file - we simulate a
bundled index.js that "exports" a HTML element to be rendered in the
container app.
Start all three web servers by running:
npm start
Then visit the main app at http://localhost:8080. The sub-apps are also previewable independently, bound to ports 8081 and 8082.