Used to store your app specific files.

Custom Webpack Configuration

The file /source/_app/webpack.app.js is your custom webpack configuration. This will merge or override the values in webpack.config.babel.js. This will provide a way to change your configuration and still get updates in the future.

Sample Custom Configuration

This edition includes an example configuration for loading, processing, and bundling SASS/SCSS. Use this sample as a template and modify as you like for working with any project asset-types.

For details into how webpack merge works, and all the options you can do, check out their page: Webpack Merge