How can I proxy an http request through two proxies using Node?

I am trying to route my http request through two proxy servers using Node's request module, but there seems to only be a way to set one proxy server. I'm using this code to route through the first proxy server:

var proxyUrl = "http://" + user + ":" + password + "@" + host + ":" + port;

var proxiedRequest = request.defaults({'proxy': proxyUrl});

But I'm a bit stuck on how to route through a second proxy.

via user1023465