docs: function (parent, siblings, index) {
                  this.parent = parent;
                  this.siblings = siblings.slice(0);
  
                  // If source node is in the target nodes
                  var i = this.siblings.indexOf(this.source);
                  if (i > -1) {
                    this.siblings.splice(i, 1);
                    if (this.source.index() < index) {
                      index--;
                    }
                  }
  
                  this.siblings.splice(index, 0, this.source);
                  this.index = index;
                }