Handling dynamic routes with page.js

I followed your blog article which is great: https://www.firebase.com/blog/2015-12-16-hosting-improvements.html

So I am using the browser sync with gulp and use it in the middleware.
middleware: [superstatic({stack: 'strict'})]

Now I am using page.js for routing and if i use simple urls for ex: page('/cart') it works but if i add a query param for ex: page('/cart/:id') the gulp fails.

This is my rewrites setup in the firebase.json

"rewrites": [
{
"source": "**",
"destination": "index.html"
}
],

How do we handle the query params