Javascript 如何将keyMirror与flow一起使用？

在我的flux/react设置中，我将ActionType定义为keyMirror

export const ActionType = keyMirror({
  START_TIMER: null,
  STOP_TIMER: null,
  PERFORM_STARTUP_CHECKS: null,
  SELECT_TASK_SERVICE:null,
  ADD_TASK: null,
  CLEAR_ALL_TASKS: null,
  COMPLETE_TASK: null,
  UNDO_COMPLETE_TASK: null,
  EDIT_TASK_TEXT: null,
});

然后，我将不同类型的操作定义如下：

export type TaskAction = {
 type: ActionType.ADD_TASK,
 text: string
} | {
 type: ActionType.COMPLETE_TASK,
 taskId: string 
}

export type TimerAction = {
  type: ActionType.START_TIMER
} | {
  type: ActionType.STOP_TIMER
}

这些不同类型的操作对应于不同的存储。例如

In TasksStore
.
.
  reduce(state: TasksList, action: TaskAction) 

In TimerStore 
.
.
reduce(state: State, action: TimerAction) 

但是，当我运行flow时，该操作无法识别

 56:         indexOfTask = state.findIndex(function(task){ return task.get('_id') === action.taskId});
                                                                                             ^^^^^^ property `taskId`. Property not found in
 56:         indexOfTask = state.findIndex(function(task){ return task.get('_id') === action.taskId});
                                                                                      ^^^^^^ object type

看见