Flow.scala

@JSExport
def main(target: html.Div): Unit = {
  ...
  /// create a chain of reactive variables
  val mouseVar = everyClick(addButton)
  val addTodo = Obs(mouseVar) {
    val desc = addDesc.value
    val time = Try{ addTime.value.toInt }.toOption.getOrElse(0)
    println(s"Adding $desc/$time")
    addNewTodo(desc, time)
  }

  val timeVar = everySecond()
  val todoTimeCount = Rx {
    thingsToDo().foldLeft(0)((x, y) => x + y.time)
  }
  val todoCount = Rx {
    thingsToDo().length
  }
  val updateTimeSummary = Rx {
    refreshTimeSummary(timeVar(), todoTimeCount())
  }
  val updateTimeSummaryStyle = Rx {
    val count = todoCount()
    if(count >= 5) {
      timeSummary.style.backgroundColor = Color.Red
    } else {
      timeSummary.style.backgroundColor = Color.White
    }
  }
  val updateTodoList = Rx {
    refreshTodoList(target, thingsToDo())
  }
  ...
}