react-router-dom: 重定向默認路由

<appLayout>
      <Switch>
          <Route path='/' exact render={()=> (
               <Redirect to={this.getDefaultRoute()}/>
           )}/>
        </Switch>
</appLayout>

根據登錄與否進入自定義路由

只能判斷根路由，子路由不受影響需做另外設置

redirectDefault() {
  const defaultState = <Route to={this.state.defaultState}/>
  const loginState = <Route to="/login"/>
  return this.state.hasLogin ? defaultState : loginState;
}