How to use the @typewriter/editor.Delta function in @typewriter/editor

}

    if (this.change) {
      from = this.change.transformPosition(from);
      if (to != null) to = this.change.transformPosition(to);
    }

    // Optimize by adding to the existing delta when possible, compose is slow
    if (this.position < from) {
      this.delta.retain(from - this.position);
      this.position = from;
    } else if (this.position) {
      this.change = this.getChange();
      from = this.change.transformPosition(from);
      if (to != null) to = this.change.transformPosition(to);
      this.delta = new Delta();
      this.delta.retain(from);
      this.position = from;
    }

    return to != null ? [ from, to ] : from;
  }
}

if (!options) options = defaultOptions;

  var walker = root.ownerDocument.createTreeWalker(root, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT, {
    acceptNode: node => {
      if (SKIP_ELEMENTS[node.nodeName]) {
        return NodeFilter.FILTER_REJECT;
      } else if (node.nodeType === Node.TEXT_NODE && node.nodeValue === '') {
        return NodeFilter.FILTER_REJECT;
      } else if (node.nodeType === Node.TEXT_NODE || options.notInDom || inDom) {
        return NodeFilter.FILTER_ACCEPT;
      } else {
        return NodeFilter.FILTER_REJECT;
      }
    }
  });
  const delta = new Delta();
  let currentBlock: any, firstBlockSeen = false, unknownBlock = false, empty = true, node: Node | null;
  let lastNode = false;

  if (options.startNode) {
    walker.currentNode = options.startNode;
    walker.previousNode();
    if (options.offset) delta.retain(options.offset, undefined);
  } else {
    walker.currentNode = root;
  }

  while ((node = walker.nextNode())) {
    if (node === options.endNode) lastNode = true;
    else if (lastNode) break;

    if (isBRPlaceholder(paper, node)) {

export function deltaFromDom(root: Element, paper: Paper, options: any = {}): Delta {
  if (!root.ownerDocument) return new Delta();
  const inDom: boolean = root.ownerDocument && root.ownerDocument.contains(root);
  const { blocks, embeds } = paper;
  if (!options) options = defaultOptions;

  var walker = root.ownerDocument.createTreeWalker(root, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT, {
    acceptNode: node => {
      if (SKIP_ELEMENTS[node.nodeName]) {
        return NodeFilter.FILTER_REJECT;
      } else if (node.nodeType === Node.TEXT_NODE && node.nodeValue === '') {
        return NodeFilter.FILTER_REJECT;
      } else if (node.nodeType === Node.TEXT_NODE || options.notInDom || inDom) {
        return NodeFilter.FILTER_ACCEPT;
      } else {
        return NodeFilter.FILTER_REJECT;
      }
    }

constructor(contents: Delta) {
    this.contents = contents;
    this.change;
    this.delta = new Delta();
    this.position = 0;
  }