@r7kamura

tab.coffee

class Tab
  constructor: ->
    @$tabs = ($ '.tab')
    @$sections = ($ '.section')
    @_idx = 0

  current_tab: =>
    @$tabs.eq(@_idx)

  current_section: =>
    $tab = @current_tab()
    type = $tab.data 'type'
    @$sections.filter ".#{type}"

  select: (@_idx) =>
    @render()

  delegate: =>
    @$tabs.off()
    @$tabs.each (idx, el) =>
      ($ el).on 'click', 'a', (event) =>
        event.preventDefault()
        @select idx

  render: =>
    $tab = @current_tab()
    $section = @current_section()

    @$tabs.removeClass 'selected'
    $tab.addClass 'selected'

    @$sections.removeClass 'selected'
    $section.addClass 'selected'

$ =>
  tab = new Tab
  tab.select(0)
  tab.delegate()

えっ、select: (@_idx) で@_idxに引数入るの、すごい

@_idxを持ってるならdata-type使わずに@$sections.eq(@_idx)で良いすね