NodeJS Zappa using @response, @request in called functions

I can do this:

require('zappajs') ->
    @get '/':-> console.log(@response)

but when I try this

require('zappajs') ->
    @get '/': -> foo()

    foo = ->
      console.log(@response)

@response is undefined. So obviously 'this' is now out of scope. I tried using the => function definition instead of -> which is meant to pass 'this' through ... but it makes no difference. I can achieve the desired result using a @helper

require('zappajs') ->
    @get '/':-> @foo()

    @helper foo: ->
        console.log(@response)

Is that the only way of doing this?