splitAt method

Leaf? splitAt(int index)

Splits this leaf node at index and returns new node.

If this is the last node in its list and index equals this node's length then this method returns null as there is nothing left to split. If there is another leaf node after this one and index equals this node's length then the next leaf node is returned.

If index equals to 0 then this node itself is returned unchanged.

In case a new node is actually split from this one, it inherits this node's style.

Implementation

Leaf? splitAt(int index) {
  assert(index >= 0 && index <= length);
  if (index == 0) {
    return this;
  }
  if (index == length) {
    return isLast ? null : next as Leaf?;
  }

  assert(this is NodeText);
  final text = _value as String;
  _value = text.substring(0, index);
  final split = Leaf(text.substring(index))..applyStyle(style);
  insertAfter(split);
  return split;
}