尝试创建调度程序时出现 TypeError in flux

There is TypeError in flux whne try to create dispatcher

我尝试在 index.js

中导入这个 class
import Dispatcher from "flux";
import React from "react";

export class CountdownDispatcher extends Dispatcher {
  handleAction(action) {
    console.log("dispatching action:", action);
    this.dispatch({
      source: "VIEW_ACTION",
      action
    });
  }
}

但是 reactjs 编译器首先在 raw 下划线并显示错误消息

Super expression must either be null or a function, not object

这是 React 和 redux 第 186 页中的示例

尝试像这样在 index.js 中导入:

import { CountDownDispatcher } from "./Flux/CountDownDispatcher";

从 "flux" 导入 {Dispatcher};