npm run build creates a dist directory with a production build of your app.
In order to serve index.html in a browser you need an HTTP server.
For example serve:
npm install -g serve
serve -s dist
The default port is 5000, but can be adjusted using the -l or --listen flags:
serve -s build -l 4000
Docs:
- https://create-react-app.dev/docs/deployment#static-server
- https://github.com/zeit/serve
- https://cli.vuejs.org/guide/deployment.html#previewing-locally