react-router为啥自己生成一个?_k=xxxx的query？

Question

代码：

效果：

补充：
无论是定义了哪个路由，都会默认带一个_k的query，不知道为啥，求解？

Answer 1

官方文档对这个有说明：
https://github.com/reactjs/react-router/...

Answer 2

import { Router, Route, IndexRoute, hashHistory } from 'react-router';
import { createHashHistory } from 'history';
var routerHistory = require('react-router').useRouterHistory;   //去掉?_k=****
const appHistory = routerHistory(createHashHistory)({ queryKey: false }) ;
import App from './app';
import Editor from './editor';
import Previewer from './previewer';
import Sbrt from './sbrt';
import React from 'react';
import ReactDOM from 'react-dom';
 /*hashHistory 有sbrt?_k=pm2dkp*/
const router = <Router history={appHistory}>   
  <Route path='/' component={App}>
    <IndexRoute component={Editor} />
      <Route path='editor' component={Editor} />
      <Route path='previewer' component={Previewer} />
      <Route path='sbrt' component={Sbrt} />
  </Route>
</Router>;

ReactDOM.render(
    router,
    document.getElementById('content')
);