Does anyone have any ideas how to make promises look nicer in CoffeeScript?

users_controller.coffee

  registerNewUser: ->
    @session.flush().then(((models)=>
      newUser = @get('content')
      @transitionToRoute('user', newUser)
    ), ((response)->
      console.log response
    ))

I'd prefer to see something along the lines of:

@session.flush
  then: (models)=>
    newUser = @get('content')
    @transitionToRoute('user', newUser)
  error: (response)->
    console.log response

but since I can't have that, I'm left with a whole shiteload of braces trying to delimit which function is which argument.

You don't actually need the parens if you don't mind only having the comma to separate the functions (visually, it's less than optimal):

registerNewUser: ->
  @session.flush().then (models)=>
    newUser = @get('content')
    @transitionToRoute('user', newUser)
  , (response)->
    console.log response