code: function getHeadingObject (heading) {
      var obj = {
        id: heading.id,
        children: [],
        nodeName: heading.nodeName,
        headingLevel: getHeadingLevel(heading),
        textContent: heading.textContent.trim()
      }
  
      if (options.includeHtml) {
        obj.childNodes = heading.childNodes
      }
  
      return obj
    }
docs: Get important properties from a heading element and store in a plain object.
  @param {HTMLElement} heading
  @return {Object}