let td = new TurndownService();

td.addRule('listItemWithBlockAsFirstChild', {
  filter: node => {
    return (
      node.nodeName === 'LI' &&
      node.firstChild &&
      // Block elements listed on https://www.w3schools.com/htmL/html_blocks.asp
      [
        'address', 'article', 'aside', 'blockquote', 'canvas', 'dd', 'div',
        'dl', 'dt', 'fieldset', 'figcaption', 'figure', 'footer', 'form',
        'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'header', 'hr', 'li', 'main',
        'nav', 'noscript', 'ol', 'p', 'pre', 'section', 'table', 'tfoot',
        'ul', 'video'
      ]
      .map(t => t.toUpperCase())
      .includes(node.firstChild.nodeName)
    );
  },
  replacement: (content, node, options) => {
    let indicator;

    if (node.parentNode.nodeName === 'OL') {
      let count = 1; // Start counting from 1
      let sibling = node.previousElementSibling;

      while (sibling) {
        if (sibling.nodeName === 'LI') {
          count++;
        }

        sibling = sibling.previousElementSibling;
      }

      indicator = `${count}.`;
    } else {
      indicator = options.bulletListMarker;
    }

    let innerMarkdown = td.turndown(node.innerHTML);

    // Add one space behind the indicator and four spaces underneath
    return `${indicator} \n\n    ${innerMarkdown}\n`;
  }
});

rules.listItem = {
  filter: 'li',
  replacement: function (content, node, options) {
    content = content
      .replace(/^\n+/, '') // remove leading newlines
      .replace(/\n+$/, '\n') // replace trailing newlines with just a single one
      .replace(/\n/gm, '\n    ') // indent
    var prefix = options.bulletListMarker + '   '
    var parent = node.parentNode

    // Check if the first child is a block-level element
    var blockElements = [
      'address', 'article', 'aside', 'blockquote', 'canvas', 'dd', 'div',
      'dl', 'dt', 'fieldset', 'figcaption', 'figure', 'footer', 'form',
      'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'header', 'hr', 'li', 'main',
      'nav', 'noscript', 'ol', 'p', 'pre', 'section', 'table', 'tfoot',
      'ul', 'video'
    ].map(function (t) {
      return t.toUpperCase()
    })

    var firstChildIsBlock = node.firstChild && blockElements.includes(node.firstChild.nodeName)

    if (parent.nodeName === 'OL') {
      var start = parent.getAttribute('start')
      var index = Array.prototype.indexOf.call(parent.children, node)
      prefix = (start ? Number(start) + index : index + 1) + '.  '
    }

    return (
      prefix + (firstChildIsBlock ? '\n\n    ' : '') + content + (node.nextSibling && !/\n$/.test(content) ? '\n' : '')
    )
  }
}