if (startNode === endNode) {
const startSplitPosInBuffer = this.positionInBuffer(startNode, startPosition.remainder);
pieceTreeBase.ts
const endSplitPosInBuffer = this.positionInBuffer(startNode, endPosition.remainder);
if (startPosition.nodeStartOffset === offset) {
if (cnt === startNode.piece.length) { // delete node
const next = startNode.next();