From 10027d5704995511c429b8a0a7d0dcd58aa16d64 Mon Sep 17 00:00:00 2001
From: Simon Bauchet <bauchet.simon@gmail.com>
Date: Mon, 22 Sep 2025 15:59:47 +0200
Subject: [PATCH 1/5] Add Indent Transformer

This transformer allows to keep indentation when switching with markdown
---
 .../src/MarkdownTransformers.ts               | 34 +++++++++++++++++++
 .../__tests__/unit/LexicalMarkdown.test.ts    | 16 +++++++++
 packages/lexical-markdown/src/index.ts        |  3 +-
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/packages/lexical-markdown/src/MarkdownTransformers.ts b/packages/lexical-markdown/src/MarkdownTransformers.ts
index cf9c5eca8c9..1d90723219a 100644
--- a/packages/lexical-markdown/src/MarkdownTransformers.ts
+++ b/packages/lexical-markdown/src/MarkdownTransformers.ts
@@ -35,6 +35,8 @@ import {
 import {
   $createLineBreakNode,
   $createTextNode,
+  $isParagraphNode,
+  $isTextNode,
   ElementNode,
   Klass,
   LexicalNode,
@@ -209,6 +211,7 @@ const CODE_SINGLE_LINE_REGEX =
   /^[ \t]*```[^`]+(?:(?:`{1,2}|`{4,})[^`]+)*```(?:[^`]|$)/;
 const TABLE_ROW_REG_EXP = /^(?:\|)(.+)(?:\|)\s?$/;
 const TABLE_ROW_DIVIDER_REG_EXP = /^(\| ?:?-*:? ?)+\|\s?$/;
+const INDENT_REGEX = /^\t+/;
 
 const createBlockNode = (
   createNode: (match: Array<string>) => ElementNode,
@@ -595,6 +598,37 @@ export const LINK: TextMatchTransformer = {
   type: 'text-match',
 };
 
+export const INDENT: TextMatchTransformer = {
+  dependencies: [],
+  export: (node, exportChildren, exportFormat) => {
+    const parentNode = node.getParent();
+    const textContent = node.getTextContent();
+    if (
+      !$isParagraphNode(parentNode) ||
+      !$isTextNode(node) ||
+      parentNode.getFirstChild() !== node
+    ) {
+      return null;
+    }
+    const indent = parentNode.getIndent();
+    const textWithFormat = exportFormat(node, textContent);
+    return textWithFormat ? '\t'.repeat(indent) + textWithFormat : null;
+  },
+  importRegExp: INDENT_REGEX,
+  regExp: INDENT_REGEX,
+  replace: (textNode, match) => {
+    const [indents] = match;
+    const parentNode = textNode.getParent();
+    if (!parentNode || !$isParagraphNode(parentNode)) {
+      return;
+    }
+    parentNode.setIndent(indents.length);
+    textNode.setTextContent(textNode.getTextContent().replace(/^\t+/, ''));
+    return textNode;
+  },
+  type: 'text-match',
+};
+
 export function normalizeMarkdown(
   input: string,
   shouldMergeAdjacentLines = false,
diff --git a/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts b/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
index ca1b5a9175d..f364bc9db67 100644
--- a/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
+++ b/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
@@ -669,6 +669,22 @@ describe('Markdown', () => {
       html: '<p><span style="white-space: pre-wrap;">[h</span><a href="https://lexical.dev"><span style="white-space: pre-wrap;">ello</span></a><a href="https://lexical.dev"><span style="white-space: pre-wrap;">world</span></a></p>',
       md: '[h[ello](https://lexical.dev)[world](https://lexical.dev)',
     },
+    {
+      html: '<p style="padding-inline-start: 40px;"><span style="white-space: pre-wrap;">Hello Word</span></p>',
+      md: '\tHello Word',
+    },
+    {
+      html: '<p style="padding-inline-start: 80px;"><span style="white-space: pre-wrap;">Hello Word</span></p>',
+      md: '\t\tHello Word',
+    },
+    {
+      html: '<p><span style="white-space: pre-wrap;">Hello\t Word</span></p>',
+      md: 'Hello\t Word',
+    },
+    {
+      html: '<p style="padding-inline-start: 40px;"><i><em style="white-space: pre-wrap;">Hello</em></i><span style="white-space: pre-wrap;"> Word</span></p>',
+      md: '\t*Hello* Word',
+    },
   ];
 
   const HIGHLIGHT_TEXT_MATCH_IMPORT: TextMatchTransformer = {
diff --git a/packages/lexical-markdown/src/index.ts b/packages/lexical-markdown/src/index.ts
index 06bd85dd492..9437a32c02d 100644
--- a/packages/lexical-markdown/src/index.ts
+++ b/packages/lexical-markdown/src/index.ts
@@ -27,6 +27,7 @@ import {
   CODE,
   HEADING,
   HIGHLIGHT,
+  INDENT,
   INLINE_CODE,
   ITALIC_STAR,
   ITALIC_UNDERSCORE,
@@ -65,7 +66,7 @@ const TEXT_FORMAT_TRANSFORMERS: Array<TextFormatTransformer> = [
   STRIKETHROUGH,
 ];
 
-const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [LINK];
+const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [INDENT, LINK];
 
 const TRANSFORMERS: Array<Transformer> = [
   ...ELEMENT_TRANSFORMERS,

From c02ef17ad51c2a1297b4342e106a3749f07421ae Mon Sep 17 00:00:00 2001
From: Simon Bauchet <bauchet.simon@gmail.com>
Date: Mon, 22 Sep 2025 17:12:42 +0200
Subject: [PATCH 2/5] Remove unused import

---
 packages/lexical-markdown/src/index.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/lexical-markdown/src/index.ts b/packages/lexical-markdown/src/index.ts
index 0725c8765a4..3b9270d0e22 100644
--- a/packages/lexical-markdown/src/index.ts
+++ b/packages/lexical-markdown/src/index.ts
@@ -28,7 +28,6 @@ import {
   ELEMENT_TRANSFORMERS,
   HEADING,
   HIGHLIGHT,
-  INDENT,
   INLINE_CODE,
   ITALIC_STAR,
   ITALIC_UNDERSCORE,

From e2a67120c6b8521841c85ad29a1c72bf389fb784 Mon Sep 17 00:00:00 2001
From: Simon Bauchet <bauchet.simon@gmail.com>
Date: Tue, 23 Sep 2025 09:29:16 +0200
Subject: [PATCH 3/5] Fix prettier error

---
 packages/lexical-markdown/src/MarkdownTransformers.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/lexical-markdown/src/MarkdownTransformers.ts b/packages/lexical-markdown/src/MarkdownTransformers.ts
index 3633a547b66..29b2af7e536 100644
--- a/packages/lexical-markdown/src/MarkdownTransformers.ts
+++ b/packages/lexical-markdown/src/MarkdownTransformers.ts
@@ -655,7 +655,10 @@ export const TEXT_FORMAT_TRANSFORMERS: Array<TextFormatTransformer> = [
   STRIKETHROUGH,
 ];
 
-export const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [INDENT, LINK];
+export const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [
+  INDENT,
+  LINK,
+];
 
 export const TRANSFORMERS: Array<Transformer> = [
   ...ELEMENT_TRANSFORMERS,

From 8cec7f1910546bca0e5b66805eaf280aff0afbb9 Mon Sep 17 00:00:00 2001
From: Simon Bauchet <simon@vivaldi.com>
Date: Tue, 4 Nov 2025 10:54:52 +0100
Subject: [PATCH 4/5] Separate INDENT transformer from default one

- Remove INDENT from TEXT_MATCH_TRANSFORMERS
- Export INDENT and use it in playground

Signed-off-by: Simon Bauchet <simon@vivaldi.com>
---
 packages/lexical-markdown/flow/LexicalMarkdown.js.flow       | 1 +
 packages/lexical-markdown/src/MarkdownTransformers.ts        | 5 +----
 .../src/__tests__/unit/LexicalMarkdown.test.ts               | 5 +++++
 packages/lexical-markdown/src/index.ts                       | 2 ++
 .../src/plugins/MarkdownTransformers/index.ts                | 2 ++
 5 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/packages/lexical-markdown/flow/LexicalMarkdown.js.flow b/packages/lexical-markdown/flow/LexicalMarkdown.js.flow
index 973fab93726..63627c9b4f7 100644
--- a/packages/lexical-markdown/flow/LexicalMarkdown.js.flow
+++ b/packages/lexical-markdown/flow/LexicalMarkdown.js.flow
@@ -127,6 +127,7 @@ declare export var CHECK_LIST: ElementTransformer;
 declare export var ORDERED_LIST: ElementTransformer;
 
 declare export var LINK: TextMatchTransformer;
+declare export var INDENT: TextMatchTransformer;
 
 declare export var TRANSFORMERS: Array<Transformer>;
 declare export var ELEMENT_TRANSFORMERS: Array<ElementTransformer>;
diff --git a/packages/lexical-markdown/src/MarkdownTransformers.ts b/packages/lexical-markdown/src/MarkdownTransformers.ts
index 8ce13e6022f..2cd44792cd0 100644
--- a/packages/lexical-markdown/src/MarkdownTransformers.ts
+++ b/packages/lexical-markdown/src/MarkdownTransformers.ts
@@ -676,10 +676,7 @@ export const TEXT_FORMAT_TRANSFORMERS: Array<TextFormatTransformer> = [
   STRIKETHROUGH,
 ];
 
-export const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [
-  INDENT,
-  LINK,
-];
+export const TEXT_MATCH_TRANSFORMERS: Array<TextMatchTransformer> = [LINK];
 
 export const TRANSFORMERS: Array<Transformer> = [
   ...ELEMENT_TRANSFORMERS,
diff --git a/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts b/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
index a27c51fa982..d2947730505 100644
--- a/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
+++ b/packages/lexical-markdown/src/__tests__/unit/LexicalMarkdown.test.ts
@@ -32,6 +32,7 @@ import {describe, expect, it} from 'vitest';
 import {
   $convertFromMarkdownString,
   $convertToMarkdownString,
+  INDENT,
   LINK,
   registerMarkdownShortcuts,
   TextMatchTransformer,
@@ -694,18 +695,22 @@ describe('Markdown', () => {
       md: '[h[ello](https://lexical.dev)[world](https://lexical.dev)',
     },
     {
+      customTransformers: [INDENT],
       html: '<p style="padding-inline-start: 40px;"><span style="white-space: pre-wrap;">Hello Word</span></p>',
       md: '\tHello Word',
     },
     {
+      customTransformers: [INDENT],
       html: '<p style="padding-inline-start: 80px;"><span style="white-space: pre-wrap;">Hello Word</span></p>',
       md: '\t\tHello Word',
     },
     {
+      customTransformers: [INDENT],
       html: '<p><span style="white-space: pre-wrap;">Hello\t Word</span></p>',
       md: 'Hello\t Word',
     },
     {
+      customTransformers: [INDENT],
       html: '<p style="padding-inline-start: 40px;"><i><em style="white-space: pre-wrap;">Hello</em></i><span style="white-space: pre-wrap;"> Word</span></p>',
       md: '\t*Hello* Word',
     },
diff --git a/packages/lexical-markdown/src/index.ts b/packages/lexical-markdown/src/index.ts
index 3b9270d0e22..f0e16aa0c31 100644
--- a/packages/lexical-markdown/src/index.ts
+++ b/packages/lexical-markdown/src/index.ts
@@ -28,6 +28,7 @@ import {
   ELEMENT_TRANSFORMERS,
   HEADING,
   HIGHLIGHT,
+  INDENT,
   INLINE_CODE,
   ITALIC_STAR,
   ITALIC_UNDERSCORE,
@@ -94,6 +95,7 @@ export {
   type ElementTransformer,
   HEADING,
   HIGHLIGHT,
+  INDENT,
   INLINE_CODE,
   ITALIC_STAR,
   ITALIC_UNDERSCORE,
diff --git a/packages/lexical-playground/src/plugins/MarkdownTransformers/index.ts b/packages/lexical-playground/src/plugins/MarkdownTransformers/index.ts
index 7498485217a..9f17da36919 100644
--- a/packages/lexical-playground/src/plugins/MarkdownTransformers/index.ts
+++ b/packages/lexical-playground/src/plugins/MarkdownTransformers/index.ts
@@ -12,6 +12,7 @@ import {
   CHECK_LIST,
   ELEMENT_TRANSFORMERS,
   ElementTransformer,
+  INDENT,
   MULTILINE_ELEMENT_TRANSFORMERS,
   TEXT_FORMAT_TRANSFORMERS,
   TEXT_MATCH_TRANSFORMERS,
@@ -315,6 +316,7 @@ export const PLAYGROUND_TRANSFORMERS: Array<Transformer> = [
   EQUATION,
   TWEET,
   CHECK_LIST,
+  INDENT,
   ...ELEMENT_TRANSFORMERS,
   ...MULTILINE_ELEMENT_TRANSFORMERS,
   ...TEXT_FORMAT_TRANSFORMERS,

From 6bec51ffcee89c3f698149a7da0e811d0f87c41d Mon Sep 17 00:00:00 2001
From: Simon <bauchet.simon@gmail.com>
Date: Fri, 21 Nov 2025 15:59:49 +0100
Subject: [PATCH 5/5] Refactor key comparison

Co-authored-by: Bob Ippolito <bob@redivi.com>
---
 packages/lexical-markdown/src/MarkdownTransformers.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/lexical-markdown/src/MarkdownTransformers.ts b/packages/lexical-markdown/src/MarkdownTransformers.ts
index b9b5a8ef000..3ca35990c1b 100644
--- a/packages/lexical-markdown/src/MarkdownTransformers.ts
+++ b/packages/lexical-markdown/src/MarkdownTransformers.ts
@@ -633,7 +633,7 @@ export const INDENT: TextMatchTransformer = {
     if (
       !$isParagraphNode(parentNode) ||
       !$isTextNode(node) ||
-      parentNode.getFirstChild() !== node
+      !node.is(parentNode.getFirstChild())
     ) {
       return null;
     }