lexical/src/LexicalSelection.ts

Lexical is an extensible text editor framework that provides excellent reliability, accessible and performance.

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

import type {LexicalEditor} from './LexicalEditor';
import type {EditorState} from './LexicalEditorState';
import type {NodeKey} from './LexicalNode';
import type {ElementNode} from './nodes/LexicalElementNode';
import type {TextFormatType} from './nodes/LexicalTextNode';

import invariant from '@lexical/internal/invariant';

import {
  $caretFromPoint,
  $caretRangeFromSelection,
  $comparePointCaretNext,
  $createLineBreakNode,
  $createParagraphNode,
  $createTextNode,
  $extendCaretToRange,
  $getAdjacentChildCaret,
  $getCaretRange,
  $getCaretRangeInDirection,
  $getChildCaret,
  $getSiblingCaret,
  $getTextNodeOffset,
  $isChildCaret,
  $isDecoratorNode,
  $isElementNode,
  $isExtendableTextPointCaret,
  $isLineBreakNode,
  $isParagraphNode,
  $isRootNode,
  $isSiblingCaret,
  $isTextNode,
  $isTextPointCaret,
  $normalizeCaret,
  $removeTextFromCaretRange,
  $rewindSiblingCaret,
  $setPointFromCaret,
  $setSelection,
  $setSelectionFromCaretRange,
  $updateRangeSelectionFromCaretRange,
  CaretRange,
  ChildCaret,
  COLLABORATION_TAG,
  type LineBreakNode,
  NodeCaret,
  PointCaret,
  SKIP_SCROLL_INTO_VIEW_TAG,
  type TextNode,
} from '.';
import {IS_FIREFOX} from './environment';
import {TEXT_TYPE_TO_FORMAT} from './LexicalConstants';
import {
  markCollapsedSelectionFormat,
  markSelectionChangeFromDOMUpdate,
} from './LexicalEvents';
import {getIsProcessingMutations} from './LexicalMutations';
import {insertRangeAfter, LexicalNode} from './LexicalNode';
import {$normalizeSelection} from './LexicalNormalization';
import {
  getActiveEditor,
  getActiveEditorState,
  isCurrentlyReadOnlyMode,
} from './LexicalUpdates';
import {SKIP_SELECTION_FOCUS_TAG} from './LexicalUpdateTags';
import {
  $findMatchingParent,
  $getCompositionKey,
  $getDOMSlot,
  $getDOMTextNode,
  $getNearestRootOrShadowRoot,
  $getNodeByKey,
  $getNodeFromDOM,
  $getRoot,
  $hasAncestor,
  $isRootOrShadowRoot,
  $isSelectionCapturedInDecorator,
  $isTokenOrSegmented,
  $isTokenOrTab,
  $setCompositionKey,
  doesContainSurrogatePair,
  getDOMSelection,
  getElementByKeyOrThrow,
  getNodeKeyFromDOMNode,
  getWindow,
  INTERNAL_$isBlock,
  isHTMLElement,
  isSelectionCapturedInDecoratorInput,
  isSelectionWithinEditor,
  removeDOMBlockCursorElement,
  scrollIntoViewIfNeeded,
  toggleTextFormatType,
} from './LexicalUtils';
import {$createTabNode, $isTabNode} from './nodes/LexicalTabNode';

const __DEV__ = process.env.NODE_ENV !== 'production';

export type TextPointType = {
  _selection: BaseSelection;
  getNode: () => TextNode;
  is: (point: PointType) => boolean;
  isBefore: (point: PointType) => boolean;
  key: NodeKey;
  offset: number;
  set: (
    key: NodeKey,
    offset: number,
    type: 'text' | 'element',
    onlyIfChanged?: boolean,
  ) => void;
  type: 'text';
};

export type ElementPointType = {
  _selection: BaseSelection;
  getNode: () => ElementNode;
  is: (point: PointType) => boolean;
  isBefore: (point: PointType) => boolean;
  key: NodeKey;
  offset: number;
  set: (
    key: NodeKey,
    offset: number,
    type: 'text' | 'element',
    onlyIfChanged?: boolean,
  ) => void;
  type: 'element';
};

export type PointType = TextPointType | ElementPointType;

export class Point {
  key: NodeKey;
  offset: number;
  type: 'text' | 'element';
  _selection: BaseSelection | null;

  constructor(key: NodeKey, offset: number, type: 'text' | 'element') {
    if (__DEV__) {
      // This prevents a circular reference error when serialized as JSON,
      // which happens on unit test failures
      Object.defineProperty(this, '_selection', {
        enumerable: false,
        writable: true,
      });
    }
    this._selection = null;
    this.key = key;
    this.offset = offset;
    this.type = type;
  }

  is(point: PointType): boolean {
    return (
      this.key === point.key &&
      this.offset === point.offset &&
      this.type === point.type
    );
  }

  isBefore(b: PointType): boolean {
    if (this.key === b.key) {
      return this.offset < b.offset;
    }
    const aCaret = $normalizeCaret($caretFromPoint(this, 'next'));
    const bCaret = $normalizeCaret($caretFromPoint(b, 'next'));
    return $comparePointCaretNext(aCaret, bCaret) < 0;
  }

  getNode(): LexicalNode {
    const key = this.key;
    const node = $getNodeByKey(key);
    if (node === null) {
      invariant(false, 'Point.getNode: node not found');
    }
    return node;
  }

  set(
    key: NodeKey,
    offset: number,
    type: 'text' | 'element',
    onlyIfChanged?: boolean,
  ): void {
    const selection = this._selection;
    const oldKey = this.key;
    if (
      onlyIfChanged &&
      this.key === key &&
      this.offset === offset &&
      this.type === type
    ) {
      return;
    }
    this.key = key;
    this.offset = offset;
    this.type = type;
    if (__DEV__) {
      const node = $getNodeByKey(key);
      invariant(
        type === 'text' ? $isTextNode(node) : $isElementNode(node),
        'PointType.set: node with key %s is %s and can not be used for a %s point',
        key,
        node ? node.__type : '[not found]',
        type,
      );
    }
    if (!isCurrentlyReadOnlyMode()) {
      if ($getCompositionKey() === oldKey) {
        $setCompositionKey(key);
      }
      if (selection !== null) {
        selection.setCachedNodes(null);
        if ($isRangeSelection(selection)) {
          selection._cachedIsBackward = null;
        }
        selection.dirty = true;
      }
    }
  }
}

export function $createPoint(
  key: NodeKey,
  offset: number,
  type: 'text' | 'element',
): PointType {
  // @ts-expect-error: intentionally cast as we use a class for perf reasons
  return new Point(key, offset, type);
}

function selectPointOnNode(point: PointType, node: LexicalNode): void {
  let key = node.__key;
  let offset = point.offset;
  let type: 'element' | 'text' = 'element';
  if ($isTextNode(node)) {
    type = 'text';
    const textContentLength = node.getTextContentSize();
    if (offset > textContentLength) {
      offset = textContentLength;
    }
  } else if (!$isElementNode(node)) {
    const nextSibling = node.getNextSibling();
    if ($isTextNode(nextSibling)) {
      key = nextSibling.__key;
      offset = 0;
      type = 'text';
    } else {
      const parentNode = node.getParent();
      if (parentNode) {
        key = parentNode.__key;
        offset = node.getIndexWithinParent() + 1;
      }
    }
  }
  point.set(key, offset, type);
}

export function $moveSelectionPointToEnd(
  point: PointType,
  node: LexicalNode,
): void {
  if ($isElementNode(node)) {
    const lastNode = node.getLastDescendant();
    if ($isElementNode(lastNode) || $isTextNode(lastNode)) {
      selectPointOnNode(point, lastNode);
    } else {
      selectPointOnNode(point, node);
    }
  } else {
    selectPointOnNode(point, node);
  }
}

function $transferStartingElementPointToTextPoint(
  start: ElementPointType,
  end: PointType,
  format: number,
  style: string,
): void {
  const element = start.getNode();
  const placementNode = element.getChildAtIndex(start.offset);
  const textNode = $createTextNode();
  textNode.setFormat(format);
  textNode.setStyle(style);
  if ($isParagraphNode(placementNode)) {
    placementNode.splice(0, 0, [textNode]);
  } else {
    const target = $isRootNode(element)
      ? $createParagraphNode().append(textNode)
      : textNode;
    if (placementNode === null) {
      element.append(target);
    } else {
      placementNode.insertBefore(target);
    }
  }
  // Transfer the element point to a text point.
  if (start.is(end)) {
    end.set(textNode.__key, 0, 'text');
  }
  start.set(textNode.__key, 0, 'text');
}

export interface BaseSelection {
  _cachedNodes: Array<LexicalNode> | null;
  dirty: boolean;

  clone(): BaseSelection;
  extract(): Array<LexicalNode>;
  getNodes(): Array<LexicalNode>;
  getTextContent(): string;
  insertText(text: string): void;
  insertRawText(text: string): void;
  is(selection: null | BaseSelection): boolean;
  insertNodes(nodes: Array<LexicalNode>): void;
  getStartEndPoints(): null | [PointType, PointType];
  isCollapsed(): boolean;
  isBackward(): boolean;
  getCachedNodes(): LexicalNode[] | null;
  setCachedNodes(nodes: LexicalNode[] | null): void;
}

export class NodeSelection implements BaseSelection {
  _nodes: Set<NodeKey>;
  _cachedNodes: Array<LexicalNode> | null;
  dirty: boolean;

  constructor(objects: Set<NodeKey>) {
    this._cachedNodes = null;
    this._nodes = objects;
    this.dirty = false;
  }

  getCachedNodes(): LexicalNode[] | null {
    return this._cachedNodes;
  }

  setCachedNodes(nodes: LexicalNode[] | null): void {
    this._cachedNodes = nodes;
  }

  is(selection: null | BaseSelection): boolean {
    if (!$isNodeSelection(selection)) {
      return false;
    }
    const a: Set<NodeKey> = this._nodes;
    const b: Set<NodeKey> = selection._nodes;
    return a.size === b.size && Array.from(a).every(key => b.has(key));
  }

  isCollapsed(): boolean {
    return false;
  }

  isBackward(): boolean {
    return false;
  }

  getStartEndPoints(): null {
    return null;
  }

  add(key: NodeKey): void {
    this.dirty = true;
    this._nodes.add(key);
    this._cachedNodes = null;
  }

  delete(key: NodeKey): void {
    this.dirty = true;
    this._nodes.delete(key);
    this._cachedNodes = null;
  }

  clear(): void {
    this.dirty = true;
    this._nodes.clear();
    this._cachedNodes = null;
  }

  has(key: NodeKey): boolean {
    return this._nodes.has(key);
  }

  clone(): NodeSelection {
    return new NodeSelection(new Set(this._nodes));
  }

  extract(): Array<LexicalNode> {
    return this.getNodes();
  }

  insertRawText(text: string): void {
    // Do nothing?
  }

  insertText(): void {
    // Do nothing?
  }

  insertNodes(nodes: Array<LexicalNode>) {
    const selectedNodes = this.getNodes();
    const selectedNodesLength = selectedNodes.length;
    const lastSelectedNode = selectedNodes[selectedNodesLength - 1];
    let selectionAtEnd: RangeSelection;
    // Insert nodes
    if ($isTextNode(lastSelectedNode)) {
      selectionAtEnd = lastSelectedNode.select();
    } else {
      const index = lastSelectedNode.getIndexWithinParent() + 1;
      selectionAtEnd = lastSelectedNode.getParentOrThrow().select(index, index);
    }
    selectionAtEnd.insertNodes(nodes);
    // Remove selected nodes
    for (let i = 0; i < selectedNodesLength; i++) {
      selectedNodes[i].remove();
    }
  }

  getNodes(): Array<LexicalNode> {
    const cachedNodes = this._cachedNodes;
    if (cachedNodes !== null) {
      return cachedNodes;
    }
    const objects = this._nodes;
    const nodes = [];
    for (const object of objects) {
      const node = $getNodeByKey(object);
      if (node !== null) {
        nodes.push(node);
      }
    }
    if (!isCurrentlyReadOnlyMode()) {
      this._cachedNodes = nodes;
    }
    return nodes;
  }

  getTextContent(): string {
    const nodes = this.getNodes();
    let textContent = '';
    for (let i = 0; i < nodes.length; i++) {
      textContent += nodes[i].getTextContent();
    }
    return textContent;
  }

  /**
   * Remove all nodes in the NodeSelection. If there were any nodes,
   * replace the selection with a new RangeSelection at the previous
   * location of the first node.
   */
  deleteNodes(): void {
    const nodes = this.getNodes();
    if (($getSelection() || $getPreviousSelection()) === this && nodes[0]) {
      const firstCaret = $getSiblingCaret(nodes[0], 'next');
      $setSelectionFromCaretRange($getCaretRange(firstCaret, firstCaret));
    }
    for (const node of nodes) {
      node.remove();
    }
  }
}

export function $isRangeSelection(x: unknown): x is RangeSelection {
  return x instanceof RangeSelection;
}

export class RangeSelection implements BaseSelection {
  format: number;
  style: string;
  anchor: PointType;
  focus: PointType;
  _cachedNodes: Array<LexicalNode> | null;
  /** @internal */
  _cachedIsBackward: boolean | null;
  dirty: boolean;

  constructor(
    anchor: PointType,
    focus: PointType,
    format: number,
    style: string,
  ) {
    this.anchor = anchor;
    this.focus = focus;
    anchor._selection = this;
    focus._selection = this;
    this._cachedNodes = null;
    this._cachedIsBackward = null;
    this.format = format;
    this.style = style;
    this.dirty = false;
  }

  getCachedNodes(): LexicalNode[] | null {
    return this._cachedNodes;
  }

  setCachedNodes(nodes: LexicalNode[] | null): void {
    this._cachedNodes = nodes;
  }

  /**
   * Used to check if the provided selections is equal to this one by value,
   * including anchor, focus, format, and style properties.
   * @param selection - the Selection to compare this one to.
   * @returns true if the Selections are equal, false otherwise.
   */
  is(selection: null | BaseSelection): boolean {
    if (!$isRangeSelection(selection)) {
      return false;
    }
    return (
      this.anchor.is(selection.anchor) &&
      this.focus.is(selection.focus) &&
      this.format === selection.format &&
      this.style === selection.style
    );
  }

  /**
   * Returns whether the Selection is "collapsed", meaning the anchor and focus are
   * the same node and have the same offset.
   *
   * @returns true if the Selection is collapsed, false otherwise.
   */
  isCollapsed(): boolean {
    return this.anchor.is(this.focus);
  }

  /**
   * Gets all the nodes in the Selection. Uses caching to make it generally suitable
   * for use in hot paths.
   *
   * See also the {@link CaretRange} APIs (starting with
   * {@link $caretRangeFromSelection}), which are likely to provide a better
   * foundation for any operation where partial selection is relevant
   * (e.g. the anchor or focus are inside an ElementNode and TextNode)
   *
   * @returns an Array containing all the nodes in the Selection
   */
  getNodes(): Array<LexicalNode> {
    const cachedNodes = this._cachedNodes;
    if (cachedNodes !== null) {
      return cachedNodes;
    }
    const range = $getCaretRangeInDirection(
      $caretRangeFromSelection(this),
      'next',
    );
    const nodes = $getNodesFromCaretRangeCompat(range);
    if (__DEV__) {
      if (this.isCollapsed() && nodes.length > 1) {
        invariant(
          false,
          'RangeSelection.getNodes() returned %s > 1 nodes in a collapsed selection',
          String(nodes.length),
        );
      }
    }
    if (!isCurrentlyReadOnlyMode()) {
      this._cachedNodes = nodes;
    }
    return nodes;
  }

  /**
   * Sets this Selection to be of type "text" at the provided anchor and focus values.
   *
   * @param anchorNode - the anchor node to set on the Selection
   * @param anchorOffset - the offset to set on the Selection
   * @param focusNode - the focus node to set on the Selection
   * @param focusOffset - the focus offset to set on the Selection
   */
  setTextNodeRange(
    anchorNode: TextNode,
    anchorOffset: number,
    focusNode: TextNode,
    focusOffset: number,
  ): this {
    this.anchor.set(anchorNode.__key, anchorOffset, 'text');
    this.focus.set(focusNode.__key, focusOffset, 'text');
    return this;
  }

  /**
   * Gets the (plain) text content of all the nodes in the selection.
   *
   * @returns a string representing the text content of all the nodes in the Selection
   */
  getTextContent(): string {
    const nodes = this.getNodes();
    if (nodes.length === 0) {
      return '';
    }
    const firstNode = nodes[0];
    const lastNode = nodes[nodes.length - 1];
    const anchor = this.anchor;
    const focus = this.focus;
    const isBefore = anchor.isBefore(focus);
    const [anchorOffset, focusOffset] = $getCharacterOffsets(this);
    let textContent = '';
    let prevWasElement = true;
    for (let i = 0; i < nodes.length; i++) {
      const node = nodes[i];
      if ($isElementNode(node) && !node.isInline()) {
        if (!prevWasElement) {
          textContent += '\n';
        }
        if (node.isEmpty()) {
          prevWasElement = false;
        } else {
          prevWasElement = true;
        }
      } else {
        prevWasElement = false;
        if ($isTextNode(node)) {
          let text = node.getTextContent();
          if (node === firstNode) {
            if (node === lastNode) {
              if (
                anchor.type !== 'element' ||
                focus.type !== 'element' ||
                focus.offset === anchor.offset
              ) {
                text =
                  anchorOffset < focusOffset
                    ? text.slice(anchorOffset, focusOffset)
                    : text.slice(focusOffset, anchorOffset);
              }
            } else {
              text = isBefore
                ? text.slice(anchorOffset)
                : text.slice(focusOffset);
            }
          } else if (node === lastNode) {
            text = isBefore
              ? text.slice(0, focusOffset)
              : text.slice(0, anchorOffset);
          }
          textContent += text;
        } else if (
          ($isDecoratorNode(node) || $isLineBreakNode(node)) &&
          (node !== lastNode || !this.isCollapsed())
        ) {
          textContent += node.getTextContent();
        }
      }
    }
    return textContent;
  }

  /**
   * Attempts to map a DOM selection range onto this Lexical Selection,
   * setting the anchor, focus, and type accordingly
   *
   * @param range a DOM Selection range conforming to the StaticRange interface.
   */
  applyDOMRange(range: StaticRange): void {
    const editor = getActiveEditor();
    const currentEditorState = editor.getEditorState();
    const lastSelection = currentEditorState._selection;
    const resolvedSelectionPoints = $internalResolveSelectionPoints(
      range.startContainer,
      range.startOffset,
      range.endContainer,
      range.endOffset,
      editor,
      lastSelection,
    );
    if (resolvedSelectionPoints === null) {
      return;
    }
    const [anchorPoint, focusPoint, dirty] = resolvedSelectionPoints;
    this.anchor.set(
      anchorPoint.key,
      anchorPoint.offset,
      anchorPoint.type,
      true,
    );
    this.focus.set(focusPoint.key, focusPoint.offset, focusPoint.type, true);
    if (dirty) {
      this.dirty = true;
    }
    // Firefox will use an element point rather than a text point in some cases,
    // so we normalize for that
    $normalizeSelection(this);
  }

  /**
   * Creates a new RangeSelection, copying over all the property values from this one.
   *
   * @returns a new RangeSelection with the same property values as this one.
   */
  clone(): RangeSelection {
    const anchor = this.anchor;
    const focus = this.focus;
    const selection = new RangeSelection(
      $createPoint(anchor.key, anchor.offset, anchor.type),
      $createPoint(focus.key, focus.offset, focus.type),
      this.format,
      this.style,
    );
    return selection;
  }

  /**
   * Toggles the provided format on all the TextNodes in the Selection.
   *
   * @param format a string TextFormatType to toggle on the TextNodes in the selection
   */
  toggleFormat(format: TextFormatType): void {
    this.format = toggleTextFormatType(this.format, format, null);
    this.dirty = true;
  }

  /**
   * Sets the value of the format property on the Selection
   *
   * @param format - the format to set at the value of the format property.
   */
  setFormat(format: number): void {
    this.format = format;
    this.dirty = true;
  }

  /**
   * Sets the value of the style property on the Selection
   *
   * @param style - the style to set at the value of the style property.
   */
  setStyle(style: string): void {
    this.style = style;
    this.dirty = true;
  }

  /**
   * Returns whether the provided TextFormatType is present on the Selection. This will be true if any node in the Selection
   * has the specified format.
   *
   * @param type the TextFormatType to check for.
   * @returns true if the provided format is currently toggled on on the Selection, false otherwise.
   */
  hasFormat(type: TextFormatType): boolean {
    const formatFlag = TEXT_TYPE_TO_FORMAT[type];
    return (this.format & formatFlag) !== 0;
  }

  /**
   * Attempts to insert the provided text into the EditorState at the current Selection.
   * converts tabs, newlines, and carriage returns into LexicalNodes.
   *
   * @param text the text to insert into the Selection
   */
  insertRawText(text: string): void {
    this.insertNodes($generateNodesFromRawText(text));
  }

  /**
   * Insert the provided text into the EditorState at the current Selection.
   *
   * @param text the text to insert into the Selection
   */
  insertText(text: string): void {
    // Now that "removeText" has been improved and does not depend on
    // insertText, insertText can be greatly simplified. The next
    // commented version is a WIP (about 5 tests fail).
    //
    // this.removeText();
    // if (text === '') {
    //   return;
    // }
    // const anchorNode = this.anchor.getNode();
    // const textNode = $createTextNode(text);
    // textNode.setFormat(this.format);
    // textNode.setStyle(this.style);
    // if ($isTextNode(anchorNode)) {
    //   const parent = anchorNode.getParentOrThrow();
    //   if (this.anchor.offset === 0) {
    //     if (parent.isInline() && !anchorNode.__prev) {
    //       parent.insertBefore(textNode);
    //     } else {
    //       anchorNode.insertBefore(textNode);
    //     }
    //   } else if (this.anchor.offset === anchorNode.getTextContentSize()) {
    //     if (parent.isInline() && !anchorNode.__next) {
    //       parent.insertAfter(textNode);
    //     } else {
    //       anchorNode.insertAfter(textNode);
    //     }
    //   } else {
    //     const [before] = anchorNode.splitText(this.anchor.offset);
    //     before.insertAfter(textNode);
    //   }
    // } else {
    //   anchorNode.splice(this.anchor.offset, 0, [textNode]);
    // }
    // const nodeToSelect = textNode.isAttached() ? textNode : anchorNode;
    // nodeToSelect.selectEnd();
    // // When composing, we need to adjust the anchor offset so that
    // // we correctly replace that right range.
    // if (
    //   textNode.isComposing() &&
    //   this.anchor.type === 'text' &&
    //   anchorNode.getTextContent() !== ''
    // ) {
    //   this.anchor.offset -= text.length;
    // }

    const anchor = this.anchor;
    const focus = this.focus;
    const format = this.format;
    const style = this.style;
    let firstPoint = anchor;
    let endPoint = focus;
    if (!this.isCollapsed() && focus.isBefore(anchor)) {
      firstPoint = focus;
      endPoint = anchor;
    }
    if (firstPoint.type === 'element') {
      $transferStartingElementPointToTextPoint(
        firstPoint,
        endPoint,
        format,
        style,
      );
    }
    if (endPoint.type === 'element') {
      $setPointFromCaret(
        endPoint,
        $normalizeCaret($caretFromPoint(endPoint, 'next')),
      );
    }
    const startOffset = firstPoint.offset;
    let endOffset = endPoint.offset;
    const selectedNodes = this.getNodes();
    const selectedNodesLength = selectedNodes.length;
    let firstNode: TextNode = selectedNodes[0] as TextNode;

    if (!$isTextNode(firstNode)) {
      invariant(false, 'insertText: first node is not a text node');
    }
    const firstNodeText = firstNode.getTextContent();
    const firstNodeTextLength = firstNodeText.length;
    const firstNodeParent = firstNode.getParentOrThrow();
    const lastIndex = selectedNodesLength - 1;
    let lastNode = selectedNodes[lastIndex];

    if (selectedNodesLength === 1 && endPoint.type === 'element') {
      endOffset = firstNodeTextLength;
      endPoint.set(firstPoint.key, endOffset, 'text');
    }

    if (
      this.isCollapsed() &&
      startOffset === firstNodeTextLength &&
      ($isTokenOrSegmented(firstNode) ||
        !firstNode.canInsertTextAfter() ||
        (!firstNodeParent.canInsertTextAfter() &&
          firstNode.getNextSibling() === null))
    ) {
      let nextSibling = firstNode.getNextSibling<TextNode>();
      if (
        !$isTextNode(nextSibling) ||
        !nextSibling.canInsertTextBefore() ||
        $isTokenOrSegmented(nextSibling)
      ) {
        nextSibling = $createTextNode();
        nextSibling.setFormat(format);
        nextSibling.setStyle(style);
        if (!firstNodeParent.canInsertTextAfter()) {
          firstNodeParent.insertAfter(nextSibling);
        } else {
          firstNode.insertAfter(nextSibling);
        }
      }
      nextSibling.select(0, 0);
      firstNode = nextSibling;
      if (text !== '') {
        this.insertText(text);
        return;
      }
    } else if (
      this.isCollapsed() &&
      startOffset === 0 &&
      ($isTokenOrSegmented(firstNode) ||
        !firstNode.canInsertTextBefore() ||
        (!firstNodeParent.canInsertTextBefore() &&
          firstNode.getPreviousSibling() === null))
    ) {
      let prevSibling = firstNode.getPreviousSibling<TextNode>();
      if (!$isTextNode(prevSibling) || $isTokenOrSegmented(prevSibling)) {
        prevSibling = $createTextNode();
        prevSibling.setFormat(format);
        if (!firstNodeParent.canInsertTextBefore()) {
          firstNodeParent.insertBefore(prevSibling);
        } else {
          firstNode.insertBefore(prevSibling);
        }
      }
      prevSibling.select();
      firstNode = prevSibling;
      if (text !== '') {
        this.insertText(text);
        return;
      }
    } else if (firstNode.isSegmented() && startOffset !== firstNodeTextLength) {
      const textNode = $createTextNode(firstNode.getTextContent());
      textNode.setFormat(format);
      firstNode.replace(textNode);
      firstNode = textNode;
    } else if (!this.isCollapsed() && text !== '') {
      // When the firstNode or lastNode parents are elements that
      // do not allow text to be inserted before or after, we first
      // clear the content. Then we normalize selection, then insert
      // the new content.
      const lastNodeParent = lastNode.getParent();

      if (
        !firstNodeParent.canInsertTextBefore() ||
        !firstNodeParent.canInsertTextAfter() ||
        ($isElementNode(lastNodeParent) &&
          (!lastNodeParent.canInsertTextBefore() ||
            !lastNodeParent.canInsertTextAfter()))
      ) {
        this.insertText('');
        $normalizeSelectionPointsForBoundaries(this.anchor, this.focus, null);
        this.insertText(text);
        return;
      }
    }

    if (selectedNodesLength === 1) {
      if ($isTokenOrTab(firstNode)) {
        const textNode = $createTextNode(text);
        textNode.select();
        firstNode.replace(textNode);
        return;
      }
      const firstNodeFormat = firstNode.getFormat();
      const firstNodeStyle = firstNode.getStyle();

      if (
        startOffset === endOffset &&
        (firstNodeFormat !== format || firstNodeStyle !== style)
      ) {
        if (firstNode.getTextContent() === '') {
          firstNode.setFormat(format);
          firstNode.setStyle(style);
        } else {
          const textNode = $createTextNode(text);
          textNode.setFormat(format);
          textNode.setStyle(style);
          textNode.select();
          if (startOffset === 0) {
            firstNode.insertBefore(textNode, false);
          } else {
            const [targetNode] = firstNode.splitText(startOffset);
            targetNode.insertAfter(textNode, false);
          }
          // When composing, we need to adjust the anchor offset so that
          // we correctly replace that right range.
          if (textNode.isComposing() && this.anchor.type === 'text') {
            this.anchor.offset -= text.length;
            this._cachedNodes = null;
            this._cachedIsBackward = null;
          }
          return;
        }
      } else if ($isTabNode(firstNode)) {
        // We don't need to check for delCount because there is only the entire selected node case
        // that can hit here for content size 1 and with canInsertTextBeforeAfter false
        const textNode = $createTextNode(text);
        textNode.setFormat(format);
        textNode.setStyle(style);
        textNode.select();
        firstNode.replace(textNode);
        return;
      }
      const delCount = endOffset - startOffset;

      firstNode = firstNode.spliceText(startOffset, delCount, text, true);
      if (firstNode.getTextContent() === '') {
        firstNode.remove();
      } else if (this.anchor.type === 'text') {
        this.format = firstNodeFormat;
        this.style = firstNodeStyle;
        if (firstNode.isComposing()) {
          // When composing, we need to adjust the anchor offset so that
          // we correctly replace that right range.
          this.anchor.offset -= text.length;
          this._cachedNodes = null;
          this._cachedIsBackward = null;
        }
      }
    } else {
      const markedNodeKeysForKeep = new Set([
        ...firstNode.getParentKeys(),
        ...lastNode.getParentKeys(),
      ]);

      // We have to get the parent elements before the next section,
      // as in that section we might mutate the lastNode.
      const firstElement = $isElementNode(firstNode)
        ? firstNode
        : firstNode.getParentOrThrow();
      let lastElement = $isElementNode(lastNode)
        ? lastNode
        : lastNode.getParentOrThrow();
      let lastElementChild = lastNode;

      // If the last element is inline, we should instead look at getting
      // the nodes of its parent, rather than itself. This behavior will
      // then better match how text node insertions work. We will need to
      // also update the last element's child accordingly as we do this.
      if (!firstElement.is(lastElement) && lastElement.isInline()) {
        // Keep traversing till we have a non-inline element parent.
        do {
          lastElementChild = lastElement;
          lastElement = lastElement.getParentOrThrow();
        } while (lastElement.isInline());
      }

      // Handle mutations to the last node.
      if (
        (endPoint.type === 'text' &&
          (endOffset !== 0 || lastNode.getTextContent() === '')) ||
        (endPoint.type === 'element' &&
          lastNode.getIndexWithinParent() < endOffset)
      ) {
        if (
          $isTextNode(lastNode) &&
          !$isTokenOrTab(lastNode) &&
          endOffset !== lastNode.getTextContentSize()
        ) {
          if (lastNode.isSegmented()) {
            const textNode = $createTextNode(lastNode.getTextContent());
            lastNode.replace(textNode);
            lastNode = textNode;
          }
          // root node selections only select whole nodes, so no text splice is necessary
          if (!$isRootNode(endPoint.getNode()) && endPoint.type === 'text') {
            lastNode = (lastNode as TextNode).spliceText(0, endOffset, '');
          }
          markedNodeKeysForKeep.add(lastNode.__key);
        } else {
          const lastNodeParent = lastNode.getParentOrThrow();
          if (
            !lastNodeParent.canBeEmpty() &&
            lastNodeParent.getChildrenSize() === 1
          ) {
            lastNodeParent.remove();
          } else {
            lastNode.remove();
          }
        }
      } else {
        markedNodeKeysForKeep.add(lastNode.__key);
      }

      // Either move the remaining nodes of the last parent to after
      // the first child, or remove them entirely. If the last parent
      // is the same as the first parent, this logic also works.
      const lastNodeChildren = lastElement.getChildren();
      const selectedNodesSet = new Set(selectedNodes);
      const firstAndLastElementsAreEqual = firstElement.is(lastElement);

      // We choose a target to insert all nodes after. In the case of having
      // and inline starting parent element with a starting node that has no
      // siblings, we should insert after the starting parent element, otherwise
      // we will incorrectly merge into the starting parent element.
      // TODO: should we keep on traversing parents if we're inside another
      // nested inline element?
      const insertionTarget =
        firstElement.isInline() && firstNode.getNextSibling() === null
          ? firstElement
          : firstNode;

      for (let i = lastNodeChildren.length - 1; i >= 0; i--) {
        const lastNodeChild = lastNodeChildren[i];

        if (
          lastNodeChild.is(firstNode) ||
          ($isElementNode(lastNodeChild) && lastNodeChild.isParentOf(firstNode))
        ) {
          break;
        }

        if (lastNodeChild.isAttached()) {
          if (
            !selectedNodesSet.has(lastNodeChild) ||
            lastNodeChild.is(lastElementChild)
          ) {
            if (!firstAndLastElementsAreEqual) {
              insertionTarget.insertAfter(lastNodeChild, false);
            }
          } else {
            lastNodeChild.remove();
          }
        }
      }

      if (!firstAndLastElementsAreEqual) {
        // Check if we have already moved out all the nodes of the
        // last parent, and if so, traverse the parent tree and mark
        // them all as being able to deleted too.
        let parent: ElementNode | null = lastElement;
        let lastRemovedParent = null;

        while (parent !== null) {
          const children = parent.getChildren();
          const childrenLength = children.length;
          if (
            childrenLength === 0 ||
            children[childrenLength - 1].is(lastRemovedParent)
          ) {
            markedNodeKeysForKeep.delete(parent.__key);
            lastRemovedParent = parent;
          }
          parent = parent.getParent();
        }
      }

      // Ensure we do splicing after moving of nodes, as splicing
      // can have side-effects (in the case of hashtags).
      if (!$isTokenOrTab(firstNode)) {
        firstNode = firstNode.spliceText(
          startOffset,
          firstNodeTextLength - startOffset,
          text,
          true,
        );
        if (firstNode.getTextContent() === '') {
          firstNode.remove();
        } else if (this.anchor.type === 'text') {
          this.format = firstNode.getFormat();
          this.style = firstNode.getStyle();
          if (firstNode.isComposing()) {
            // When composing, we need to adjust the anchor offset so that
            // we correctly replace that right range.
            this.anchor.offset -= text.length;
            this._cachedNodes = null;
            this._cachedIsBackward = null;
          }
        }
      } else if (startOffset === firstNodeTextLength) {
        firstNode.select();
      } else {
        const textNode = $createTextNode(text);
        textNode.select();
        firstNode.replace(textNode);
      }

      // Remove all selected nodes that haven't already been removed.
      for (let i = 1; i < selectedNodesLength; i++) {
        const selectedNode = selectedNodes[i];
        const key = selectedNode.__key;
        if (!markedNodeKeysForKeep.has(key)) {
          selectedNode.remove();
        }
      }
    }
  }

  /**
   * Removes the text in the Selection, adjusting the EditorState accordingly.
   */
  removeText(): void {
    const isCurrentSelection = $getSelection() === this;
    const newRange = $removeTextFromCaretRange($caretRangeFromSelection(this));
    $updateRangeSelectionFromCaretRange(this, newRange);
    if (isCurrentSelection && $getSelection() !== this) {
      $setSelection(this);
    }
  }

  // TO-DO: Migrate this method to the new utility function $forEachSelectedTextNode (share similar logic)
  /**
   * Applies the provided format to the TextNodes in the Selection, splitting or
   * merging nodes as necessary.
   *
   * @param formatType the format type to apply to the nodes in the Selection.
   * @param alignWithFormat a 32-bit integer representing formatting flags to align with.
   */
  formatText(
    formatType: TextFormatType,
    alignWithFormat: number | null = null,
  ): void {
    if (this.isCollapsed()) {
      this.toggleFormat(formatType);
      // When changing format, we should stop composition
      $setCompositionKey(null);
      return;
    }

    const selectedNodes = this.getNodes();
    const selectedTextNodes: Array<TextNode> = [];
    for (const selectedNode of selectedNodes) {
      if ($isTextNode(selectedNode)) {
        selectedTextNodes.push(selectedNode);
      }
    }
    const applyFormatToElements = (alignWith: number | null) => {
      selectedNodes.forEach(node => {
        if ($isElementNode(node)) {
          const newFormat = node.getFormatFlags(formatType, alignWith);
          node.setTextFormat(newFormat);
        }
      });
    };

    const selectedTextNodesLength = selectedTextNodes.length;
    if (selectedTextNodesLength === 0) {
      this.toggleFormat(formatType);
      // When changing format, we should stop composition
      $setCompositionKey(null);
      applyFormatToElements(alignWithFormat);
      return;
    }

    const anchor = this.anchor;
    const focus = this.focus;
    const isBackward = this.isBackward();
    const startPoint = isBackward ? focus : anchor;
    const endPoint = isBackward ? anchor : focus;

    let firstIndex = 0;
    let firstNode = selectedTextNodes[0];
    let startOffset = startPoint.type === 'element' ? 0 : startPoint.offset;

    // In case selection started at the end of text node use next text node
    if (
      startPoint.type === 'text' &&
      startOffset === firstNode.getTextContentSize()
    ) {
      firstIndex = 1;
      firstNode = selectedTextNodes[1];
      startOffset = 0;
    }

    if (firstNode == null) {
      return;
    }

    const firstNextFormat = firstNode.getFormatFlags(
      formatType,
      alignWithFormat,
    );
    applyFormatToElements(firstNextFormat);

    const lastIndex = selectedTextNodesLength - 1;
    let lastNode = selectedTextNodes[lastIndex];
    const endOffset =
      endPoint.type === 'text'
        ? endPoint.offset
        : lastNode.getTextContentSize();

    // Single node selected
    if (firstNode.is(lastNode)) {
      // No actual text is selected, so do nothing.
      if (startOffset === endOffset) {
        return;
      }
      // The entire node is selected or it is token, so just format it
      if (
        $isTokenOrSegmented(firstNode) ||
        (startOffset === 0 && endOffset === firstNode.getTextContentSize())
      ) {
        firstNode.setFormat(firstNextFormat);
      } else {
        // Node is partially selected, so split it into two nodes
        // add style the selected one.
        const splitNodes = firstNode.splitText(startOffset, endOffset);
        const replacement = startOffset === 0 ? splitNodes[0] : splitNodes[1];
        replacement.setFormat(firstNextFormat);

        // Update selection only if starts/ends on text node
        if (startPoint.type === 'text') {
          startPoint.set(replacement.__key, 0, 'text');
        }
        if (endPoint.type === 'text') {
          endPoint.set(replacement.__key, endOffset - startOffset, 'text');
        }
      }

      this.format = firstNextFormat;

      return;
    }
    // Multiple nodes selected
    // The entire first node isn't selected, so split it
    if (startOffset !== 0 && !$isTokenOrSegmented(firstNode)) {
      [, firstNode] = firstNode.splitText(startOffset);
      startOffset = 0;
    }
    firstNode.setFormat(firstNextFormat);

    const lastNextFormat = lastNode.getFormatFlags(formatType, firstNextFormat);
    // If the offset is 0, it means no actual characters are selected,
    // so we skip formatting the last node altogether.
    if (endOffset > 0) {
      if (
        endOffset !== lastNode.getTextContentSize() &&
        !$isTokenOrSegmented(lastNode)
      ) {
        [lastNode] = lastNode.splitText(endOffset);
      }
      lastNode.setFormat(lastNextFormat);
    }

    // Process all text nodes in between
    for (let i = firstIndex + 1; i < lastIndex; i++) {
      const textNode = selectedTextNodes[i];
      const nextFormat = textNode.getFormatFlags(formatType, lastNextFormat);
      textNode.setFormat(nextFormat);
    }

    // Update selection only if starts/ends on text node
    if (startPoint.type === 'text') {
      startPoint.set(firstNode.__key, startOffset, 'text');
    }
    if (endPoint.type === 'text') {
      endPoint.set(lastNode.__key, endOffset, 'text');
    }

    this.format = firstNextFormat | lastNextFormat;
  }

  /**
   * Attempts to "intelligently" insert an arbitrary list of Lexical nodes into the EditorState at the
   * current Selection according to a set of heuristics that determine how surrounding nodes
   * should be changed, replaced, or moved to accommodate the incoming ones.
   *
   * @param nodes - the nodes to insert
   */
  insertNodes(nodes: Array<LexicalNode>): void {
    if (nodes.length === 0) {
      return;
    }
    if (!this.isCollapsed()) {
      this.removeText();
    }
    if (this.anchor.key === 'root') {
      this.insertParagraph();
      const selection = $getSelection();
      invariant(
        $isRangeSelection(selection),
        'Expected RangeSelection after insertParagraph',
      );
      return selection.insertNodes(nodes);
    }

    const firstPoint = this.isBackward() ? this.focus : this.anchor;
    const firstNode = firstPoint.getNode();
    const firstBlock = $findMatchingParent(firstNode, INTERNAL_$isBlock);

    const last = nodes[nodes.length - 1]!;

    // CASE 1: insert inside a code block
    if ($isElementNode(firstBlock) && '__language' in firstBlock) {
      if ('__language' in nodes[0]) {
        this.insertText(nodes[0].getTextContent());
      } else {
        const index = $removeTextAndSplitBlock(this);
        firstBlock.splice(index, 0, nodes);
        last.selectEnd();
      }
      return;
    }

    // CASE 2: All elements of the array are inline
    const notInline = (node: LexicalNode) =>
      ($isElementNode(node) || $isDecoratorNode(node)) && !node.isInline();

    if (!nodes.some(notInline)) {
      invariant(
        $isElementNode(firstBlock),
        'Expected node %s of type %s to have a block ElementNode ancestor',
        firstNode.constructor.name,
        firstNode.getType(),
      );
      const index = $removeTextAndSplitBlock(this);
      firstBlock.splice(index, 0, nodes);
      last.selectEnd();
      return;
    }

    // CASE 3: At least 1 element of the array is not inline
    const blocksParent = $wrapInlineNodes(nodes);
    const nodeToSelect = blocksParent.getLastDescendant()!;
    const blocks = blocksParent.getChildren();
    const isMergeable = (node: LexicalNode): node is ElementNode =>
      $isElementNode(node) &&
      INTERNAL_$isBlock(node) &&
      !node.isEmpty() &&
      $isElementNode(firstBlock) &&
      (!firstBlock.isEmpty() || firstBlock.canMergeWhenEmpty());

    const shouldInsert = !$isElementNode(firstBlock) || !firstBlock.isEmpty();
    const insertedParagraph = shouldInsert ? this.insertParagraph() : null;
    const lastToInsert: LexicalNode | undefined = blocks[blocks.length - 1];
    let firstToInsert: LexicalNode | undefined = blocks[0];
    if (isMergeable(firstToInsert)) {
      invariant(
        $isElementNode(firstBlock),
        'Expected node %s of type %s to have a block ElementNode ancestor',
        firstNode.constructor.name,
        firstNode.getType(),
      );
      firstBlock.append(...firstToInsert.getChildren());
      firstToInsert = blocks[1];
    }
    if (firstToInsert) {
      invariant(
        firstBlock !== null,
        'Expected node %s of type %s to have a block ancestor',
        firstNode.constructor.name,
        firstNode.getType(),
      );
      insertRangeAfter(firstBlock, firstToInsert);
    }
    const lastInsertedBlock = $findMatchingParent(
      nodeToSelect,
      INTERNAL_$isBlock,
    );

    if (
      insertedParagraph &&
      $isElementNode(lastInsertedBlock) &&
      (insertedParagraph.canMergeWhenEmpty() || INTERNAL_$isBlock(lastToInsert))
    ) {
      lastInsertedBlock.append(...insertedParagraph.getChildren());
      insertedParagraph.remove();
    }
    if ($isElementNode(firstBlock) && firstBlock.isEmpty()) {
      firstBlock.remove();
    }

    nodeToSelect.selectEnd();

    // To understand this take a look at the test "can wrap post-linebreak nodes into new element"
    const lastChild = $isElementNode(firstBlock)
      ? firstBlock.getLastChild()
      : null;
    if ($isLineBreakNode(lastChild) && lastInsertedBlock !== firstBlock) {
      lastChild.remove();
    }
  }

  /**
   * Inserts a new ParagraphNode into the EditorState at the current Selection
   *
   * @returns the newly inserted node.
   */
  insertParagraph(): ElementNode | null {
    if (this.anchor.key === 'root') {
      const paragraph = $createParagraphNode();
      $getRoot().splice(this.anchor.offset, 0, [paragraph]);
      paragraph.select();
      return paragraph;
    }
    const index = $removeTextAndSplitBlock(this);
    const block = $findMatchingParent(this.anchor.getNode(), INTERNAL_$isBlock);
    invariant(
      $isElementNode(block),
      'Expected ancestor to be a block ElementNode',
    );
    const firstToAppend = block.getChildAtIndex(index);
    const nodesToInsert = firstToAppend
      ? [firstToAppend, ...firstToAppend.getNextSiblings()]
      : [];
    const newBlock = block.insertNewAfter(this, false) as ElementNode | null;
    if (newBlock) {
      newBlock.append(...nodesToInsert);
      newBlock.selectStart();
      return newBlock;
    }
    // if newBlock is null, it means that block is of type CodeNode.
    return null;
  }

  /**
   * Inserts a logical linebreak, which may be a new LineBreakNode or a new ParagraphNode, into the EditorState at the
   * current Selection.
   */
  insertLineBreak(selectStart?: boolean): void {
    const lineBreak = $createLineBreakNode();
    this.insertNodes([lineBreak]);
    // this is used in MacOS with the command 'ctrl-O' (openLineBreak)
    if (selectStart) {
      const parent = lineBreak.getParentOrThrow();
      const index = lineBreak.getIndexWithinParent();
      parent.select(index, index);
    }
  }

  /**
   * Extracts the nodes in the Selection, splitting nodes where necessary
   * to get offset-level precision.
   *
   * @returns The nodes in the Selection
   */
  extract(): Array<LexicalNode> {
    const selectedNodes = [...this.getNodes()];
    const selectedNodesLength = selectedNodes.length;
    let firstNode = selectedNodes[0];
    let lastNode = selectedNodes[selectedNodesLength - 1];
    const [anchorOffset, focusOffset] = $getCharacterOffsets(this);
    const isBackward = this.isBackward();
    const [startPoint, endPoint] = isBackward
      ? [this.focus, this.anchor]
      : [this.anchor, this.focus];
    const [startOffset, endOffset] = isBackward
      ? [focusOffset, anchorOffset]
      : [anchorOffset, focusOffset];

    if (selectedNodesLength === 0) {
      return [];
    } else if (selectedNodesLength === 1) {
      if ($isTextNode(firstNode) && !this.isCollapsed()) {
        const splitNodes = firstNode.splitText(startOffset, endOffset);
        const node = startOffset === 0 ? splitNodes[0] : splitNodes[1];
        if (node) {
          startPoint.set(node.getKey(), 0, 'text');
          endPoint.set(node.getKey(), node.getTextContentSize(), 'text');
          return [node];
        }
        return [];
      }
      return [firstNode];
    }

    if ($isTextNode(firstNode)) {
      if (startOffset === firstNode.getTextContentSize()) {
        selectedNodes.shift();
      } else if (startOffset !== 0) {
        [, firstNode] = firstNode.splitText(startOffset);
        selectedNodes[0] = firstNode;
        startPoint.set(firstNode.getKey(), 0, 'text');
      }
    }
    if ($isTextNode(lastNode)) {
      const lastNodeText = lastNode.getTextContent();
      const lastNodeTextLength = lastNodeText.length;
      if (endOffset === 0) {
        selectedNodes.pop();
      } else if (endOffset !== lastNodeTextLength) {
        [lastNode] = lastNode.splitText(endOffset);
        selectedNodes[selectedNodes.length - 1] = lastNode;
        endPoint.set(lastNode.getKey(), lastNode.getTextContentSize(), 'text');
      }
    }
    return selectedNodes;
  }

  /**
   * Modifies the Selection according to the parameters and a set of heuristics that account for
   * various node types. Can be used to safely move or extend selection by one logical "unit" without
   * dealing explicitly with all the possible node types.
   *
   * @param alter the type of modification to perform
   * @param isBackward whether or not selection is backwards
   * @param granularity the granularity at which to apply the modification
   */
  modify(
    alter: 'move' | 'extend',
    isBackward: boolean,
    granularity: 'character' | 'word' | 'lineboundary',
  ): void {
    if (
      $modifySelectionAroundDecoratorsAndBlocks(
        this,
        alter,
        isBackward,
        granularity,
      )
    ) {
      return;
    }
    const collapse = alter === 'move';

    const editor = getActiveEditor();
    const domSelection = getDOMSelection(getWindow(editor));

    if (!domSelection) {
      return;
    }
    const blockCursorElement = editor._blockCursorElement;
    const rootElement = editor._rootElement;
    const focusNode = this.focus.getNode();
    // Remove the block cursor element if it exists. This will ensure selection
    // works as intended. If we leave it in the DOM all sorts of strange bugs
    // occur. :/
    if (
      rootElement !== null &&
      blockCursorElement !== null &&
      $isElementNode(focusNode) &&
      !focusNode.isInline() &&
      !focusNode.canBeEmpty()
    ) {
      removeDOMBl