Microfront End Notes (Angular 8+)

Once the single-spa-angular schematic is installed, you lose the dev workflow of npm run serve. This prevents the app from running as a standalone.
The following changes need to be done:
- Create an environtment.plugin.ts that's only used when building the single-spa plugin. This allows you to choose the proper route to load depending on what you're building.
- Modify the angular.json to recognize the plugin configuration (replaces environment.ts with environment.plugin.ts).
- Modify extra-webpack.config.json to not do anything if building for standalone. For plugin, make it change the webpack entry property to build the main.single-spa.tsx instead.
- For PROD build, enable sourcemaps inside angular.json

Microfront End Notes (React 16+)

Needed to add plugin.tsx which would be the entry point for building the single-spa plugin.
Need to use webpack.config.json in order to build react project as a loadable SystemJS module.

For React, In order to load chunks, the systemjs-webpack-interop lib is required to define the __WEBPACK__PUBLIC__PATH. This forces the portal to load chunks of the loaded app from the host it originated from.
For Angular, this is handled by the single-spa-angular lib.
CORS has to be enabled on the hosting servers of the assets