module.exports で インスタンスとクラス両方返す方法？

foo.js

// export the function that instantiate the class and return it with same option
module.exports = function foo(opts) {
  return new Foo(opts);
};

module.exports.Foo = Foo;

main.js

var foo = require('foo') // foo is isntance

var Foo = require('foo').Foo // Foo is class