How would you write a service layer for this Node.js React application?

https://github.com/simonrenoult/nodejs-application-architecture/blob/master/index.jsI looked at it and realized the business logic is written in the router file. I am wondering if how you would personally write a service layer for the router file. Can you explain your design choices?

Submitted November 13, 2019 at 02:29PM by jesusscript