ant-design/components/form/demo/label-debug.tsx

import React from 'react';
import { Form, Input, Typography } from 'antd';

const App: React.FC = () => (
  <Form
    name="label-ellipsis"
    labelCol={{ span: 8 }}
    wrapperCol={{ span: 16 }}
    style={{ maxWidth: 600 }}
  >
    <Form.Item
      label={
        <Typography.Text ellipsis>
          longtextlongtextlongtextlongtextlongtextlongtextlongtext
        </Typography.Text>
      }
      name="username"
    >
      <Input />
    </Form.Item>

    <Form.Item
      label={
        <Typography.Text ellipsis>
          longtext longtext longtext longtext longtext longtext longtext
        </Typography.Text>
      }
      name="password"
    >
      <Input.Password />
    </Form.Item>
  </Form>
);

export default App;