Why do production React apps break from environment variables?
Because env vars are not set in the hosting dashboard, so the app falls back to default or localhost values. Always set production env vars in the dashboard before deploying, so the app calls the right backend.
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More FAQs in Common Mistakes Developers Make While Finalizing React Projects
Because build errors only appear on the host if you skip it. Run npm run build locally first and fix any errors, so the deploy succeeds. A failed build on the host is far worse than catching it locally.
Yes, or use a logger that respects environment. Leaving debug logs clutters the production console and can leak data. Clean up debug code as part of finalizing.
Because without one, an unhandled error shows a blank screen for the user, which is a terrible experience. Error boundaries wrap the app so errors show a fallback instead of white-screening the user.
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