     ->
       if value == None
         value = f()
-        f = null
+        f = undefined
       value
   toString: (obj) ->
     try


addPropertyInitValueToStream = (property, stream) ->
  justInitValue = new EventStream describe(property, "justInitValue"), (sink) ->
    value = null
    unsub = property.subscribeInternal (event) ->
      if event.hasValue()
        value = event

    pushing = false
    ended = false
    @hasSubscribers = -> subscriptions.length > 0
    prevError = undefined
    unsubscribeFromSource = nop
    removeSub = (subscription) ->
      subscriptions = _.without(subscription, subscriptions)
