Package Exports
- react-app-rewired/scripts/build
- react-app-rewired/scripts/start
This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (react-app-rewired) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.
Readme

Rewire Your App
Tweak the create-react-app webpack config(s) without using 'eject' and without creating a fork of the react-scripts.
All the benefits of create-react-app without the limitations of "no config". You can add plugins, loaders whatever you need.
All you have to do is create your app using create-react-app and than rewire it.
#How to rewire your create-react-app project
1) Install react-app-rewired
$ npm install react-app-rewired --save
2) Create a config-overrides.js
file in the root directory
/* config-overrides.js */
module.exports = function override(config, env) {
//do stuff with the webpack config...
return config;
}
see the examples
+-- your-project
| +-- config-overrides.js
| +-- node_modules
| +-- package.json
| +-- public
| +-- README.md
| +-- src
3) Add the the npm run
scripts
/* package.json */
"scripts": {
"rewire:start": "node ./node_modules/react-app-rewired/scripts/start",
"rewire:build": "node ./node_modules/react-app-rewired/scripts/build"
}
4) Start the Dev Server or Build your app using the rewired config
$ npm run rewire:start
$ npm run rewire:build