bool visitPseudoClassSelector()

in lib/src/query_selector.dart [134:181]

• 25 lines of code
• 16 McCabe index (conditional complexity)

  bool visitPseudoClassSelector(PseudoClassSelector node) {
    switch (node.name) {
      // http://dev.w3.org/csswg/selectors-4/#structural-pseudos

      // http://dev.w3.org/csswg/selectors-4/#the-root-pseudo
      case 'root':
        // TODO(jmesserly): fix when we have a .ownerDocument pointer
        // return _element == _element.ownerDocument.rootElement;
        return _element!.localName == 'html' && _element!.parentNode == null;

      // http://dev.w3.org/csswg/selectors-4/#the-empty-pseudo
      case 'empty':
        return _element!.nodes
            .any((n) => !(n is Element || n is Text && n.text.isNotEmpty));

      // http://dev.w3.org/csswg/selectors-4/#the-blank-pseudo
      case 'blank':
        return _element!.nodes.any((n) => !(n is Element ||
            n is Text && n.text.runes.any((r) => !isWhitespaceCC(r))));

      // http://dev.w3.org/csswg/selectors-4/#the-first-child-pseudo
      case 'first-child':
        return _element!.previousElementSibling == null;

      // http://dev.w3.org/csswg/selectors-4/#the-last-child-pseudo
      case 'last-child':
        return _element!.nextElementSibling == null;

      // http://dev.w3.org/csswg/selectors-4/#the-only-child-pseudo
      case 'only-child':
        return _element!.previousElementSibling == null &&
            _element!.nextElementSibling == null;

      // http://dev.w3.org/csswg/selectors-4/#link
      case 'link':
        return _element!.attributes['href'] != null;

      case 'visited':
        // Always return false since we aren't a browser. This is allowed per:
        // http://dev.w3.org/csswg/selectors-4/#visited-pseudo
        return false;
    }

    // :before, :after, :first-letter/line can't match DOM elements.
    if (_isLegacyPsuedoClass(node.name)) return false;

    throw _unimplemented(node);
  }