code: function resolveModule(cwd, dir, filename) {
  	dir = pathJoin(cwd, dir);
  
  	var filepath = pathJoin(dir, filename);
  	var resolved = require.resolve(filepath);
  
  	return resolved && {
  		cwd: cwd,
  		dir: dir,
  		path: resolved
  	};
  }
docs: Does X/file.ext exist? Does X/file.ext.js exist? Does X/file.ext/index.js exist? Else, throw