code: function SimpleSlice(array, start_i, del_count, len, deleted_elements) {
    for (var i = 0; i < del_count; i++) {
      var index = start_i + i;
      if (index in array) {
        var current = array[index];
        %CreateDataProperty(deleted_elements, i, current);
      }
    }
  }
docs: This is part of the old simple-minded splice.  We are using it either because the receiver is not an array (so we have no choice) or because we know we are not deleting or moving a lot of elements.