require-jade.js

var fs = require('fs');
var jade = require('jade');
require.extensions['.jade'] = function(module, data) { 
  var content = fs.readFileSync(module.filename);
  var str = 'module.exports = ' + jade.compile(content, {filename: module.filename});
  console.log(module.filename, str); 
  return module._compile(str, data);
};

And the function above is not going to get a string but an object that has a filename property.