The backend will serve the library (list of songs with metadata)
To start app run next command
npm run start
and go to http://localhost:3000/api/library/songs to get JSON output
To extend this api please go to src/backend/controllers/ and src/backend/routes/
For songs api used Itunes public API https://affiliate.itunes.apple.com/resources/documentation/itunes-store-web-service-search-api/