docusaurus/packages/docusaurus-theme-classic/src/theme/CodeBlock/index.js

/**
 * Copyright (c) 2017-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import React, {useEffect, useState, useRef} from 'react';
import classnames from 'classnames';
import Highlight, {defaultProps} from 'prism-react-renderer';
import defaultTheme from 'prism-react-renderer/themes/palenight';
import Clipboard from 'clipboard';
import rangeParser from 'parse-numeric-range';
import useDocusaurusContext from '@docusaurus/useDocusaurusContext';
import styles from './styles.module.css';

const highlightLinesRangeRegex = /{([\d,-]+)}/;

export default ({children, className: languageClassName, metastring}) => {
  const {
    siteConfig: {
      themeConfig: {prism = {}},
    },
  } = useDocusaurusContext();
  const [showCopied, setShowCopied] = useState(false);
  const target = useRef(null);
  const button = useRef(null);
  let highlightLines = [];

  if (metastring && highlightLinesRangeRegex.test(metastring)) {
    const highlightLinesRange = metastring.match(highlightLinesRangeRegex)[1];
    highlightLines = rangeParser.parse(highlightLinesRange).filter(n => n > 0);
  }

  useEffect(() => {
    let clipboard;

    if (button.current) {
      clipboard = new Clipboard(button.current, {
        target: () => target.current,
      });
    }

    return () => {
      if (clipboard) {
        clipboard.destroy();
      }
    };
  }, [button.current, target.current]);

  let language =
    languageClassName && languageClassName.replace(/language-/, '');

  if (!language && prism.defaultLanguage) {
    language = prism.defaultLanguage;
  }

  const handleCopyCode = () => {
    window.getSelection().empty();
    setShowCopied(true);

    setTimeout(() => setShowCopied(false), 2000);
  };

  return (
    <div className={styles.codeBlockWrapper}>
      <button
        ref={button}
        type="button"
        aria-label="Copy code to clipboard"
        className={styles.copyButton}
        onClick={handleCopyCode}>
        {showCopied ? 'Copied' : 'Copy'}
      </button>

      <Highlight
        {...defaultProps}
        theme={prism.theme || defaultTheme}
        code={children.trim()}
        language={language}>
        {({className, style, tokens, getLineProps, getTokenProps}) => (
          <pre className={classnames(className, styles.codeBlock)}>
            <code
              ref={target}
              className={classnames(className, styles.codeBlockLines)}
              style={style}>
              {tokens.map((line, i) => {
                const lineProps = getLineProps({line, key: i});

                if (highlightLines.includes(i + 1)) {
                  lineProps.className = `${lineProps.className} docusaurus-highlight-code-line`;
                }

                return (
                  <div key={i} {...lineProps}>
                    {line.map((token, key) => (
                      <span key={key} {...getTokenProps({token, key})} />
                    ))}
                  </div>
                );
              })}
            </code>
          </pre>
        )}
      </Highlight>
    </div>
  );
};