code: function shouldIgnoreNode (node) {
    return node.nodeType === TEXT_NODE
      || node.nodeType === COMMENT_NODE
      || node.nodeType === CDATA_NODE;
  }
docs: We ignore raw text (usually whitespace), <!-- xml comments -->,
  and raw CDATA nodes.
  
  @param {Element} node
  @returns {Boolean}
  @api private