antDesign菜单组件的"奇怪"写法

ant Design5的官方文档，Menu菜单上开始第一个案例是这样写的：

import React, { useState } from 'react';
import { AppstoreOutlined, MailOutlined, SettingOutlined } from '@ant-design/icons';
// menuProps的类型
import type { MenuProps } from 'antd';
import { Menu } from 'antd';
// 定义items 很麻烦对吧？
const items: MenuProps['items'] = [
  {
    label: 'Navigation One',
    key: 'mail',
    icon: <MailOutlined />,
  },
  {
    label: 'Navigation Two',
    key: 'app',
    icon: <AppstoreOutlined />,
    disabled: true,
  },
  {
    label: 'Navigation Three - Submenu',
    key: 'SubMenu',
    icon: <SettingOutlined />,
    children: [
      {
        type: 'group',
        label: 'Item 1',
        children: [
          {
            label: 'Option 1',
            key: 'setting:1',
          },
          {
            label: 'Option 2',
            key: 'setting:2',
          },
        ],
      },
      {
        type: 'group',
        label: 'Item 2',
        children: [
          {
            label: 'Option 3',
            key: 'setting:3',
          },
          {
            label: 'Option 4',
            key: 'setting:4',
          },
        ],
      },
    ],
  },
  {
    label: (
      <a href="https://ant.design" target="_blank" rel="noopener noreferrer">
        Navigation Four - Link
      </a>
    ),
    key: 'alipay',
  },
];

const App: React.FC = () => {
  const [current, setCurrent] = useState('mail');

  const onClick: MenuProps['onClick'] = (e) => {
    console.log('click ', e);
    setCurrent(e.key);
  };

  return <Menu onClick={onClick} selectedKeys={[current]} mode="horizontal" items={items} />;
};

export default App;

在看下第二个例子：

这里使用了getItem的工

import React from 'react';
import { AppstoreOutlined, MailOutlined, SettingOutlined } from '@ant-design/icons';
import type { MenuProps } from 'antd';
import { Menu } from 'antd';
// 它使用 Required 类型工具从 MenuProps 类型中获取 items 属性，并使用 [number] 索引访问其中的元素类型
type MenuItem = Required<MenuProps>['items'][number];

// item工具函数，省去了很多模板代码
function getItem(
  label: React.ReactNode,
  key: React.Key,
  icon?: React.ReactNode,
  children?: MenuItem[],
  type?: 'group',
): MenuItem {
  return {
    key,
    icon,
    children,
    label,
    type,
  } as MenuItem;
}

const items: MenuProps['items'] = [
  getItem('Navigation One', 'sub1', <MailOutlined />, [
    getItem('Item 1', 'g1', null, [getItem('Option 1', '1'), getItem('Option 2', '2')], 'group'),
    getItem('Item 2', 'g2', null, [getItem('Option 3', '3'), getItem('Option 4', '4')], 'group'),
  ]),

  getItem('Navigation Two', 'sub2', <AppstoreOutlined />, [
    getItem('Option 5', '5'),
    getItem('Option 6', '6'),
    getItem('Submenu', 'sub3', null, [getItem('Option 7', '7'), getItem('Option 8', '8')]),
  ]),

  { type: 'divider' },

  getItem('Navigation Three', 'sub4', <SettingOutlined />, [
    getItem('Option 9', '9'),
    getItem('Option 10', '10'),
    getItem('Option 11', '11'),
    getItem('Option 12', '12'),
  ]),

  getItem('Group', 'grp', null, [getItem('Option 13', '13'), getItem('Option 14', '14')], 'group'),
];

const App: React.FC = () => {
  const onClick: MenuProps['onClick'] = (e) => {
    console.log('click ', e);
  };

  return (
    <Menu
      onClick={onClick}
      style={{ width: 256 }}
      defaultSelectedKeys={['1']}
      defaultOpenKeys={['sub1']}
      mode="inline"
      items={items}
    />
  );
};

export default App;