bolt.new/packages/bolt/app/components/chat/CodeBlock.tsx

import { memo, useEffect, useState } from 'react';
import {
  bundledLanguages,
  codeToHtml,
  isSpecialLang,
  type BundledLanguage,
  type BundledTheme,
  type SpecialLanguage,
} from 'shiki';
import { classNames } from '~/utils/classNames';
import { createScopedLogger } from '~/utils/logger';
import styles from './CodeBlock.module.scss';

const logger = createScopedLogger('CodeBlock');

interface CodeBlockProps {
  code: string;
  language?: BundledLanguage;
  theme?: BundledTheme | SpecialLanguage;
}

export const CodeBlock = memo(({ code, language, theme }: CodeBlockProps) => {
  const [html, setHTML] = useState<string | undefined>(undefined);
  const [copied, setCopied] = useState(false);

  const copyToClipboard = () => {
    if (copied) {
      return;
    }

    navigator.clipboard.writeText(code);

    setCopied(true);

    setTimeout(() => {
      setCopied(false);
    }, 2000);
  };

  useEffect(() => {
    if (language && !isSpecialLang(language) && !(language in bundledLanguages)) {
      logger.warn(`Unsupported language '${language}'`);
    }

    logger.trace(`Language = ${language}`);

    const processCode = async () => {
      setHTML(await codeToHtml(code, { lang: language ?? 'plaintext', theme: theme ?? 'dark-plus' }));
    };

    processCode();
  }, [code]);

  return (
    <div className="relative group">
      <div
        className={classNames(
          styles.CopyButtonContainer,
          'bg-white absolute top-[10px] right-[10px] rounded-md z-10 text-lg flex items-center justify-center opacity-0 group-hover:opacity-100',
          {
            'rounded-l-0 opacity-100': copied,
          },
        )}
      >
        <button
          className={classNames(
            'flex items-center p-[6px] justify-center before:bg-white before:rounded-l-md before:text-gray-500 before:border-r before:border-gray-300',
            {
              'before:opacity-0': !copied,
              'before:opacity-100': copied,
            },
          )}
          title="Copy Code"
          onClick={() => copyToClipboard()}
        >
          <div className="i-ph:clipboard-text-duotone"></div>
        </button>
      </div>
      <div dangerouslySetInnerHTML={{ __html: html ?? '' }}></div>
    </div>
  );
});