Named routes and a Railscast

I'm looking at railscast#102 ( #102 Auto-Complete Association - RailsCasts ) and when I implement it, a certain named ( "formatted_channelnotes_path(:js)" ) route is used in:

<%= text_field_with_auto_complete :channel, :channelnote_name, { :size => 15 }, { :url => formatted_channelnotes_path(:js), :method => :get, :param_name => 'search' } %>

Which results in:

NoMethodError in Channels#uplog

Showing app/views/channels/_channelnotesfield.html.erb where line #10 raised:

undefined method `formatted_channelnotes_path' for #<ActionView::Base: 0x634b128>

How do I specify this named route? I can see routes specified in my / config/routes.rb but I don;t understand how I should specify it to this javascript file. Can someone please show me how to do this? Thanks, RVince