Use the Production Build

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If you’re benchmarking or experiencing performance problems in your React apps, make sure you’re testing with the minified production build.

By default, React includes many helpful warnings. These warnings are very useful in development. However, they make React larger and slower so you should make sure to use the production version when you deploy the app.

If you aren’t sure whether your build process is set up correctly, you can check it by installing React Developer Tools for Chrome (https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi).

If you visit a site with React in production mode, the icon will have a dark background:

If you visit a site with React in development mode, the icon will have a red background:

It is expected that you use the development mode when working on your app, and the production mode when deploying your app to the users.