ant-design/components/input/demo/show-count.tsx

import React from 'react';
import { Input } from 'antd';

const { TextArea } = Input;

const onChange = (e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>) => {
  console.log('Change:', e.target.value);
};

const App: React.FC = () => (
  <>
    <Input showCount maxLength={20} onChange={onChange} />
    <br />
    <br />
    <TextArea showCount maxLength={100} onChange={onChange} />
  </>
);

export default App;