There is already a system for building a NPM node package from a Deno package, called dnt (deno to node). It's maintained by some Deno team members. Here's a blog post they wrote about porting "Oak" (a deno HTTP server framework) to Node: https://deno.com/blog/dnt-oak

The nice thing about Deno conceptually, is that it's much more similar to the browser platform than node is. It uses ES6 only, has things like `fetch` built-in by default, and generally follows browser standards around interfaces like Request, Response, etc. Instead of needing a complicated build process to make Node code work on the browser, now we have a complicated build process to make Deno/Browser code work on Node. ¯\_(ツ)_/¯