You can use create-react-app with webpack-bundle-analyzer without ejecting:

npm run build -- --stats

This generates the file bundle-stats.json in the public directory, which you then can use with webpack-bundle-analyzer:

npx webpack-bundle-analyzer ./build/bundle-stats-json

The feature is currently undocumented (documentation was removed), because the CRA team find the labelling of webpack-bundle-analyzer misleading, see: https://github.com/facebook/create-react-app/issues/4563