   arrowClicked: ->
     { stepId, direction } = @props
 
-    if (direction is 'right' and not TaskStepStore.get(stepId).is_completed)
+    if (direction is 'right' and stepId and not TaskStepStore.get(stepId).is_completed)
       TaskStepStore.on('step.completed', @transition)
       TaskStepActions.complete(stepId)
     else

    stepKey: React.PropTypes.number
    goToStep: React.PropTypes.func


  transition: ->
    { stepId, stepKey, direction, goToStep } = @props

React = require 'react'
{TaskStore} = require '../../../flux/task'
{TaskStepStore, TaskStepActions} = require '../../../flux/task-step'
keymaster = require 'keymaster'
KEYBINDING_SCOPE  = 'reading-progress'

module.exports = React.createClass
  propTypes:
