anchor.diff:  
     /// Inserts `elements` at position `index` to the list at `path`.
     void insertAll(String path, int index, Iterable elements) {
  -    jsElement.callMethod(
  -        'splice',
  +    jsElement.callMethod('splice',
           [path, index, 0]..addAll(elements.map((element) => jsValue(element))));
     }
   
  
positive.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]);
  
negative.code: 
    /// 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]) {
      int numToReplace = end - start;
      jsElement.callMethod(
          'splice',
          [path, start, numToReplace]
            ..addAll(iterable
                .skip(skipCount)
                .take(numToReplace)
                .map((element) => jsValue(element))));
    }
  }
  