Extract Markdown Headings and Their Levels

function extractMarkdownHeadings(markdown) {
  const headings = [];
  const regex = /^(#{1,6})\s(.+)$/gm;
  let match;
  while ((match = regex.exec(markdown)) !== null) {
    headings.push({
      level: match[1].length,
      text: match[2].trim()
    });
  }
  return headings;
}

How it works: This snippet utilizes a global, multiline regular expression to scan Markdown text for lines that begin with one to six hash symbols followed by a space. It captures both the hash symbols (to determine the heading level) and the heading text itself, returning them as an array of structured objects useful for building navigation.