timeoutIfLast.coffee

  app.service 'timeoutIfLast', [
    '$q'
    '$interval'
    ($q, $interval) ->
      # delayの間, watchFnがtrueのまま持続したときに実行されるpromiseを返す
      #
      # @param {Function} watchFn
      # @param {Number} delay ms
      # @param {Number} [watchInterval] ms
      # @return {Promise}
      (watchFn, delay, watchInterval=100) ->
        deferred = $q.defer()

        currentDelay = 0

        timer = $interval(->
          if watchFn()
            currentDelay += watchInterval
            if currentDelay >= delay
              deferred.resolve()
              $interval.cancel(timer)
          else
            deferred.reject()
            $interval.cancel(timer)
        , watchInterval)

        deferred.promise