react 浏览器刷新/关闭 拦截

  componentWillMount () {
    // 拦截判断是否离开当前页面
    window.addEventListener('beforeunload', this.beforeunload);
  }
  componentWillUnmount () {
    // 销毁拦截判断是否离开当前页面
    window.removeEventListener('beforeunload', this.beforeunload);
  }
  beforeunload (e) {
    let confirmationMessage = '你确定离开此页面吗?';
    (e || window.event).returnValue = confirmationMessage;
    return confirmationMessage;
  }