This is originally from @williamcoates on github but fix some stuff so it works.

connect-assets-hbs-helpers.coffee

    hbs = require 'hbs'
    
    #for css
    hbs.registerHelper 'css', (file, media) ->
        media = "all" unless media.substring?
        st = ''
        require('xml2js').parseString css(file), (err, xml) ->
            st = """<link href="#{xml.link.$.href}" media="#{media}" rel="stylesheet" type="text/css"/>"""
        st

    #for js 
    hbs.registerHelper 'js', (path) ->
       js(path)

    #for images
    hbs.registerHelper 'img', (file) ->
        """<img src="#{img(file)}"/>"""