How to pass context into a AJAX request

$.ajax-context.js.coffee

#
# from a future commit on spree_wizard, https://github.com/think602/spree_wizard
#

SpreeWizard.Views.Steps ||= {}

class SpreeWizard.Views.Steps.IndexView extends Marionette.CompositeView
  itemView: SpreeWizard.Views.Steps.StepView
  template: JST["backbone/templates/steps/index"]
  el: '#steps'
  
  onRender: ->  
    _.each(@collection.models, ((model_step, index, list) ->
      url_param_key = "step" + (index+1).toString()
      variant_id = @getURLParameter(url_param_key)
      @getVariant(model_step) if variant_id
    ), @)
    
  getURLParameter: (name) -> 
    decodeURIComponent((new RegExp("[?|&]#{name}=([^&;]+?)(&|##|;|$)").exec(location.search) || [null,""] )[1].replace(/\+/g, '%20'))||null;
      
  getVariant: (model_step) ->
    view_step = @children.findByModel(model_step)
    
    url = "/api/variants?q[id_eq]=" + model_step.get('id')
    
    $.ajax(url, 
      dataType: 'json'
      context: @
      success: (data, textStatus, jqXHR) ->
        @selectVariant(data.variants[0]) if data.count == 1
    )
  
  selectVariant: (variant_attributes) ->
    console.log variant_attributes