UML Class Diagram from Node.js Express based app?

Does anyone ever worked on making Class Diagram (UML) from Node.js Express based app? We built web app as semestral work but Teacher said he wants Class Diagram for it :D I know Class diagram is the thing from what you make the app but we need to do it oppositely. Should I just say that controllers, services, models, routers (generally javascript modules) are classes and just connect them how they are in HTTP lifetime?

I tried npm module called WAWI but it's made for reverse engineering :D (Including everything, really everything)