anchor.diff:    void render(VContext context) {
       if ((flags & (elementFlag | componentFlag | rootFlag)) != 0) {
         final html.Element r = ref;
  -      var c;
  -
  -      if (type != null) {
  -        if (c == null) {
  -          c = r.classes;
  -        }
  -        c.add(type);
  -      }
   
         if (attrs != null) {
           attrs.forEach((k, v) {
  
positive.code:   }
  }
  
  /// Find changes between Lists [a] and [b] and apply this changes to Set [n].
  void updateClasses(List a, List b, Set n) {
    if (a != null && a.length > 0) {
      if (b == null || b.length == 0) {
        n.removeAll(a);
      } else {
        final aLength = a.length;
        final bLength = b.length;
  
        if (aLength * bLength <= 16) {
          final visited = new List(bLength);
  
          for (var aItem in a) {
            var removed = true;
  
            for (var i = 0; i < bLength; i++) {
              final bItem = b[i];
  
              if (aItem == bItem) {
                removed = false;
                visited[i] = true;
                break;
              }
            }
            if (removed) {
              n.remove(aItem);
            }
          }
          for (var i = 0; i < bLength; i++) {
            if (visited[i] != true) {
              n.add(b[i]);
            }
          }
        } else {
          final bIndex = new HashMap();
  
          for (var bItem in b) {
            bIndex[bItem] = false;
          }
  
          for (var aItem in a) {
            if (!bIndex.containsKey(aItem)) {
              n.remove(aItem);
            } else {
              bIndex[aItem] = true;
            }
          }
  
          bIndex.forEach((k, v) {
            if (v == false) {
              n.add(k);
            }
          });
        }
      }
    } else if (b != null && b.length > 0) {
      n.addAll(b);
    }
    return null;
  }
  
  void writeAttrsToHtmlString(StringBuffer b, Map<String, String> attrs) {
  
negative.code:         });
        }
  
        if ((flags & (elementFlag | componentFlag)) != 0) {
          String className = type;
          if (classes != null) {
            final classesString = classes.join(' ');
            className = className == null ? classesString : className + ' ' + classesString;
          }
          if (className != null) {
            data = className;
            r.className = className;
          }
        } else {
          //html.DomTokenList classList;
          html.CssClassSet classList;
  
          if (type != null) {
            //classList = r.classList;
            classList = r.classes;
            classList.add(type);
          }
  
          if (classes != null) {
            if (classList == null) {
              //classList = r.classList;
              classList = r.classes;
            }
            for (var i = 0; i < classes.length; i++) {
              classList.add(classes[i]);
            }
          }
        }
  
        if ((flags & componentFlag) != 0) {
  