server.js is a stupid insecure web server, loads what is requested and does some "hi " => "yoyoma " processing
node server.js&
a.js is just a simple program that loads /.b and prints some stuff, but ./b will be loaded through HTTP:
require("./hookhttp");
console.log("in a, before require ./b");
const b = require("./b");
console.log("in a, after require ./b");
console.log("in a, b says: " + b.hi());
console.log("end of a");b.js in turn loads ./dir/c (again fetched over HTTP) and prints its own source code (via fs module, loaded locally).
Here be dragons. Insecure, incomplete, blah blah. To fix this you need to tidy it up, implement proper client-side and server-side caching, module directory resolving, proper module naming, error handling, built-in handling and probably a lot more.
This hack is Public Domain so do what you want