anchor.diff:      }
     }
   
  -  print('Unwrapped exception.');
     // Just return the exception. We should not wrap it because in case
     // the exception comes from the DOM, it is a JavaScript
     // object backed by a native Dart class.
  
positive.code:   }
  
    if (JS('bool', r'# instanceof TypeError', ex)) {
      print('In TypeError.');
      var match;
      // Using JS to give type hints to the compiler to help tree-shaking.
      // TODO(ahe): That should be unnecessary due to type inference.
  
negative.code:   // detect specific errors, so check for this first.
    if (JS('bool', '"number" in #', ex)
        && JS('bool', 'typeof #.number == "number"', ex)) {
      int number = JS('int', '#.number', ex);
  
      // From http://msdn.microsoft.com/en-us/library/ie/hc53e755(v=vs.94).aspx
  