ant-design/components/typography/Title.tsx

import * as React from 'react';

import { devUseWarning } from '../_util/warning';
import type { BlockProps } from './Base';
import Base from './Base';

const TITLE_ELE_LIST = [1, 2, 3, 4, 5] as const;

export interface TitleProps
  extends Omit<BlockProps<'h1' | 'h2' | 'h3' | 'h4' | 'h5'>, 'strong'>,
    Omit<
      React.HTMLAttributes<HTMLHeadElement>,
      'type' | keyof BlockProps<'h1' | 'h2' | 'h3' | 'h4' | 'h5'>
    > {
  level?: (typeof TITLE_ELE_LIST)[number];
}

const Title = React.forwardRef<HTMLElement, TitleProps>((props, ref) => {
  const { level = 1, ...restProps } = props;
  let component: keyof JSX.IntrinsicElements;

  if (process.env.NODE_ENV !== 'production') {
    const warning = devUseWarning('Typography.Title');

    warning(
      TITLE_ELE_LIST.includes(level),
      'usage',
      'Title only accept `1 | 2 | 3 | 4 | 5` as `level` value. And `5` need 4.6.0+ version.',
    );
  }

  if (TITLE_ELE_LIST.includes(level)) {
    component = `h${level}`;
  } else {
    component = 'h1';
  }

  return <Base ref={ref} {...restProps} component={component} />;
});

export default Title;