gistfile1.js

// in some global context. this is just a sketch, not intended to be deployed.

function watchModuleUrl(url, parent) {
  var resolvedModule = resolveModulePath(request, parent);
  var id = resolvedModule[0],
      paths = resolvedModule[1];

  findModulePath(url, paths, function (filename) {
    if (!filename) return;

    process.watchFile(filename, function () {
      loadPromise = loadModule(url, parent);
      loadPromise.addCallback(function (module) {
        parent.unCacheModule(url);
        parent.requireAsync(url).addCallback(child) {
          child.moduleCache = {};
          process.mixin(child.moduleCache, globalModuleCache);
        };
    });
  });
}

// in Module.loadScript

function requireHotAsync (url) {
  watchModuleUrl(url, self);
  return requireAsync(url);
}

function requireHot (url) {
  return requireHotAsync(url).wait();
}

require.hot = requireHot;