From 710a0ce01f102af8c54c75d670c43b2e80b70721 Mon Sep 17 00:00:00 2001
From: Gerard Rovira <gerardrovira@meta.com>
Date: Wed, 27 Nov 2024 13:02:41 -0500
Subject: [PATCH] address comments

---
 packages/lexical-utils/src/markSelection.ts   | 21 ++++++-------------
 .../lexical-utils/src/positionNodeOnRange.ts  | 11 +++-------
 packages/lexical/src/LexicalUtils.ts          |  4 ++--
 packages/lexical/src/index.ts                 |  2 ++
 4 files changed, 13 insertions(+), 25 deletions(-)

diff --git a/packages/lexical-utils/src/markSelection.ts b/packages/lexical-utils/src/markSelection.ts
index 1f834935f80..382b57b4bb7 100644
--- a/packages/lexical-utils/src/markSelection.ts
+++ b/packages/lexical-utils/src/markSelection.ts
@@ -9,8 +9,10 @@
 import {
   $getSelection,
   $isRangeSelection,
+  $isTextNode,
   type EditorState,
   ElementNode,
+  getDOMTextNode,
   type LexicalEditor,
   TextNode,
 } from 'lexical';
@@ -64,7 +66,7 @@ export default function markSelection(
         currentAnchorOffset !== previousAnchorOffset ||
         currentAnchorNodeKey !== previousAnchorNode.getKey() ||
         (currentAnchorNode !== previousAnchorNode &&
-          (!(previousAnchorNode instanceof TextNode) ||
+          (!$isTextNode(previousAnchorNode) ||
             currentAnchorNode.updateDOM(
               previousAnchorNode,
               currentAnchorNodeDOM,
@@ -76,7 +78,7 @@ export default function markSelection(
         currentFocusOffset !== previousFocusOffset ||
         currentFocusNodeKey !== previousFocusNode.getKey() ||
         (currentFocusNode !== previousFocusNode &&
-          (!(previousFocusNode instanceof TextNode) ||
+          (!$isTextNode(previousFocusNode) ||
             currentFocusNode.updateDOM(
               previousFocusNode,
               currentFocusNodeDOM,
@@ -106,8 +108,8 @@ export default function markSelection(
             lastHTMLElement = focusHTMLElement;
             lastOffset = focus.offset;
           }
-          const firstHTMLElementTextChild = firstTextChild(firstHTMLElement);
-          const lastHTMLElementtextChild = firstTextChild(lastHTMLElement);
+          const firstHTMLElementTextChild = getDOMTextNode(firstHTMLElement);
+          const lastHTMLElementtextChild = getDOMTextNode(lastHTMLElement);
           range.setStart(
             firstHTMLElementTextChild || firstHTMLElement,
             firstOffset,
@@ -160,14 +162,3 @@ export default function markSelection(
     },
   );
 }
-
-function firstTextChild(node: Node): null | Text {
-  let current: Node | null = node;
-  while (current !== null) {
-    if (current instanceof Text) {
-      return current;
-    }
-    current = current.firstChild;
-  }
-  return null;
-}
diff --git a/packages/lexical-utils/src/positionNodeOnRange.ts b/packages/lexical-utils/src/positionNodeOnRange.ts
index 20bcd5292f9..2ae7df5e35e 100644
--- a/packages/lexical-utils/src/positionNodeOnRange.ts
+++ b/packages/lexical-utils/src/positionNodeOnRange.ts
@@ -6,9 +6,8 @@
  *
  */
 
-import type {LexicalEditor} from 'lexical';
-
 import {createRectsFromDOMRange} from '@lexical/selection';
+import {isHTMLElement, type LexicalEditor} from 'lexical';
 import invariant from 'shared/invariant';
 
 import px from './px';
@@ -21,11 +20,7 @@ const mutationObserverConfig = {
 };
 
 function prependDOMNode(parent: HTMLElement, node: HTMLElement) {
-  if (parent.hasChildNodes()) {
-    parent.insertBefore(node, parent.firstChild);
-  } else {
-    parent.append(node);
-  }
+  parent.insertBefore(node, parent.firstChild);
 }
 
 /**
@@ -126,7 +121,7 @@ export default function mlcPositionNodeOnRange(
       return stop();
     }
     const currentParentDOMNode = currentRootDOMNode.parentElement;
-    if (!(currentParentDOMNode instanceof HTMLElement)) {
+    if (currentParentDOMNode === null || !isHTMLElement(currentParentDOMNode)) {
       return stop();
     }
     stop();
diff --git a/packages/lexical/src/LexicalUtils.ts b/packages/lexical/src/LexicalUtils.ts
index 28b4f57e943..f4cc88ac86a 100644
--- a/packages/lexical/src/LexicalUtils.ts
+++ b/packages/lexical/src/LexicalUtils.ts
@@ -194,14 +194,14 @@ export function $isTokenOrSegmented(node: TextNode): boolean {
   return node.isToken() || node.isSegmented();
 }
 
-function isDOMNodeLexicalTextNode(node: Node): node is Text {
+export function isDOMTextNode(node: Node): node is Text {
   return node.nodeType === DOM_TEXT_TYPE;
 }
 
 export function getDOMTextNode(element: Node | null): Text | null {
   let node = element;
   while (node != null) {
-    if (isDOMNodeLexicalTextNode(node)) {
+    if (isDOMTextNode(node)) {
       return node;
     }
     node = node.firstChild;
diff --git a/packages/lexical/src/index.ts b/packages/lexical/src/index.ts
index 5f1eae58210..562c7c4e387 100644
--- a/packages/lexical/src/index.ts
+++ b/packages/lexical/src/index.ts
@@ -180,10 +180,12 @@ export {
   $setSelection,
   $splitNode,
   getDOMSelection,
+  getDOMTextNode,
   getEditorPropertyFromDOMNode,
   getNearestEditorFromDOMNode,
   isBlockDomNode,
   isDocumentFragment,
+  isDOMTextNode,
   isDOMUnmanaged,
   isHTMLAnchorElement,
   isHTMLElement,