anchor.diff:  
     /// Copies the objects of `iterable`, skipping `skipCount` objects first, into
     /// the range `start`, inclusive, to `end`, exclusive, of the list at `path`.
  -  void setRange(
  -      String path, int start, int end, Iterable iterable, [int skipCount = 0]) {
  +  void setRange(String path, int start, int end, Iterable iterable,
  +      [int skipCount = 0]) {
       int numToReplace = end - start;
       jsElement.callMethod(
           'splice',
           [path, start, numToReplace]
  -          ..addAll(
  -            iterable
  -            .skip(skipCount)
  -            .take(numToReplace)
  -            .map((element) => jsValue(element))));
  +          ..addAll(iterable
  +              .skip(skipCount)
  +              .take(numToReplace)
  +              .map((element) => jsValue(element))));
     }
   }
  
positive.code: 
    /// Inserts `elements` at position `index` to the list at `path`.
    void insertAll(String path, int index, Iterable elements) {
      jsElement.callMethod(
          'splice',
          [path, index, 0]..addAll(elements.map((element) => jsValue(element))));
    }
  
  
negative.code:   bool removeItem(String path, value) {
      List list = get(path);
      var index = list.indexOf(value);
  
      /// Assumes the lists are in sync! We are in lots of trouble if they aren't
      /// though, and verifying it is a lot more expensive.
      jsElement.callMethod('splice', [path, index, 1]);
  