     @setState
       second: @state.second + 1
 
-  mixins: [@SetIntervalMixin]
+  mixins: [SetIntervalMixin]
 
   getInitialState: ->
     @question_count = @props.data.questions.length


  tick_start: ->
    unless @interval
      @interval = setInterval(@tick, 1000)
      @setState
        play: true
        is_start: true

SetIntervalMixin =
  componentWillMount: ->
    @intervals = []

  setInterval: ->
    @intervals.push setInterval.apply(null, arguments)

  componentWillUnmount: ->
    @intervals.map(clearInterval)

@ExerciseBase = React.createClass
  outputSeconds: ->
    @getFormattedTime @state.second

