I just popped open DevTools on an SPA I made using create-react-app with default settings. Sure enough the minified production JavaScript uses shortened variable names. This is default configuration for Webpack, which is pretty widely used throughout (and outside) the React ecosystem.
Interestingly you can still view the unminified source, since create-react-app generates source maps by default.
Interestingly you can still view the unminified source, since create-react-app generates source maps by default.