How to run React.js on Scala REST API server?

Question

Scala

Good time of the day. I have a React.js application which I created with create-react-app. Also I have a Scala REST API which uses Akka-HTTP. To build React, I use npm run build. I want Scala to send index.html to the client with another static file. I started writing routes for static files, but this method has been used for a long time and maybe today there is something else to do it automatically. Can you advise me how to solve this problem?
Thanks