kg-agent/html/answer_markdown.js

/* Markdown rendering shared by streamed and completed assistant replies.
 * Marked 17.0.5 is vendored with its license. Only allowlisted DOM is copied. */
(function () {
  const tags = new Set('P BR H1 H2 H3 H4 H5 H6 UL OL LI STRONG EM DEL BLOCKQUOTE PRE CODE HR TABLE THEAD TBODY TR TH TD A'.split(' '));
  const drop = new Set('SCRIPT STYLE IFRAME OBJECT EMBED SVG MATH TEMPLATE FORM INPUT IMG VIDEO AUDIO SOURCE LINK META'.split(' '));
  function safeCopy(node) {
    if (node.nodeType === Node.TEXT_NODE) return document.createTextNode(node.textContent);
    const fragment = document.createDocumentFragment();
    if (node.nodeType !== Node.ELEMENT_NODE || drop.has(node.tagName)) return fragment;
    const out = tags.has(node.tagName) ? document.createElement(node.tagName.toLowerCase()) : fragment;
    if (node.tagName === 'A') {
      const href = node.getAttribute('href') || '';
      try {
        const url = new URL(href, location.href);
        if (['http:', 'https:', 'mailto:'].includes(url.protocol)) {
          out.setAttribute('href', url.href);
          out.setAttribute('target', '_blank');
          out.setAttribute('rel', 'noopener noreferrer');
        }
      } catch (_) {}
    }
    if (node.tagName === 'OL' && /^\d+$/.test(node.getAttribute('start') || '')) out.setAttribute('start', node.getAttribute('start'));
    for (const child of node.childNodes) out.appendChild(safeCopy(child));
    return out;
  }
  window.renderAnswer = function (element, text) {
    element.classList.add('markdown-body');
    const raw = String(text || '');
    try {
      const template = document.createElement('template');
      template.innerHTML = marked.parse(raw, {gfm: true, breaks: true, async: false});
      const clean = document.createDocumentFragment();
      for (const node of template.content.childNodes) clean.appendChild(safeCopy(node));
      element.replaceChildren(clean);
    } catch (_) {
      element.textContent = raw;
    }
  };
})();