export function parseLines()

in packages/docusaurus-theme-common/src/utils/codeBlockUtils.ts [106:171]

• 51 lines of code
• 9 McCabe index (conditional complexity)

export function parseLines(
  content: string,
  metastring?: string,
  language?: string,
): {
  /**
   * The highlighted lines, 0-indexed. e.g. `[0, 1, 4]` means the 1st, 2nd, and
   * 5th lines are highlighted.
   */
  highlightLines: number[];
  /**
   * The clean code without any magic comments (only if highlight range isn't
   * present in the metastring).
   */
  code: string;
} {
  let code = content.replace(/\n$/, '');
  // Highlighted lines specified in props: don't parse the content
  if (metastring && highlightLinesRangeRegex.test(metastring)) {
    const highlightLinesRange = metastring.match(highlightLinesRangeRegex)!
      .groups!.range!;
    const highlightLines = rangeParser(highlightLinesRange)
      .filter((n) => n > 0)
      .map((n) => n - 1);
    return {highlightLines, code};
  }
  if (language === undefined) {
    return {highlightLines: [], code};
  }
  const directiveRegex = getAllMagicCommentDirectiveStyles(language);
  // go through line by line
  const lines = code.split('\n');
  let highlightBlockStart: number;
  let highlightRange = '';
  // loop through lines
  for (let lineNumber = 0; lineNumber < lines.length; ) {
    const line = lines[lineNumber]!;
    const match = line.match(directiveRegex);
    if (match !== null) {
      const directive = match.slice(1).find((item) => item !== undefined);
      switch (directive) {
        case 'highlight-next-line':
          highlightRange += `${lineNumber},`;
          break;

        case 'highlight-start':
          highlightBlockStart = lineNumber;
          break;

        case 'highlight-end':
          highlightRange += `${highlightBlockStart!}-${lineNumber - 1},`;
          break;

        default:
          break;
      }
      lines.splice(lineNumber, 1);
    } else {
      // lines without directives are unchanged
      lineNumber += 1;
    }
  }
  const highlightLines = rangeParser(highlightRange);
  code = lines.join('\n');
  return {highlightLines, code};
}