From a8e46cd0a7f969ebcce45eb6fd04dda9b51ecd7a Mon Sep 17 00:00:00 2001
From: Jiuqing Song <jisong@microsoft.com>
Date: Thu, 6 Jun 2024 12:17:07 -0700
Subject: [PATCH] improve

---
 .../lib/command/paste/mergePasteContent.ts      |  2 +-
 .../lib/corePlugin/cache/domIndexerImpl.ts      |  2 +-
 .../lib/constants}/EmptySegmentFormat.ts        |  4 ++--
 .../roosterjs-content-model-dom/lib/index.ts    |  1 +
 .../lib/modelApi/editing/mergeModel.ts          | 17 ++---------------
 5 files changed, 7 insertions(+), 19 deletions(-)
 rename packages/{roosterjs-content-model-core/lib/corePlugin/cache => roosterjs-content-model-dom/lib/constants}/EmptySegmentFormat.ts (67%)

diff --git a/packages/roosterjs-content-model-core/lib/command/paste/mergePasteContent.ts b/packages/roosterjs-content-model-core/lib/command/paste/mergePasteContent.ts
index c491851941b..1985248838c 100644
--- a/packages/roosterjs-content-model-core/lib/command/paste/mergePasteContent.ts
+++ b/packages/roosterjs-content-model-core/lib/command/paste/mergePasteContent.ts
@@ -1,7 +1,7 @@
 import { createDomToModelContextForSanitizing } from '../createModelFromHtml/createDomToModelContextForSanitizing';
-import { EmptySegmentFormat } from '../../corePlugin/cache/EmptySegmentFormat';
 import {
     ChangeSource,
+    EmptySegmentFormat,
     cloneModel,
     domToContentModel,
     getSegmentTextFormat,
diff --git a/packages/roosterjs-content-model-core/lib/corePlugin/cache/domIndexerImpl.ts b/packages/roosterjs-content-model-core/lib/corePlugin/cache/domIndexerImpl.ts
index 35ef9fdf4c5..41783fb0666 100644
--- a/packages/roosterjs-content-model-core/lib/corePlugin/cache/domIndexerImpl.ts
+++ b/packages/roosterjs-content-model-core/lib/corePlugin/cache/domIndexerImpl.ts
@@ -1,5 +1,5 @@
-import { EmptySegmentFormat } from './EmptySegmentFormat';
 import {
+    EmptySegmentFormat,
     createSelectionMarker,
     createText,
     getObjectKeys,
diff --git a/packages/roosterjs-content-model-core/lib/corePlugin/cache/EmptySegmentFormat.ts b/packages/roosterjs-content-model-dom/lib/constants/EmptySegmentFormat.ts
similarity index 67%
rename from packages/roosterjs-content-model-core/lib/corePlugin/cache/EmptySegmentFormat.ts
rename to packages/roosterjs-content-model-dom/lib/constants/EmptySegmentFormat.ts
index 5408d42f816..4eb04cf14be 100644
--- a/packages/roosterjs-content-model-core/lib/corePlugin/cache/EmptySegmentFormat.ts
+++ b/packages/roosterjs-content-model-dom/lib/constants/EmptySegmentFormat.ts
@@ -1,9 +1,9 @@
 import type { ContentModelSegmentFormat } from 'roosterjs-content-model-types';
 
 /**
- * @internal
+ * Provide a default empty instance of segment format with all its properties
  */
-export const EmptySegmentFormat: Required<ContentModelSegmentFormat> = {
+export const EmptySegmentFormat: Readonly<Required<ContentModelSegmentFormat>> = {
     backgroundColor: '',
     fontFamily: '',
     fontSize: '',
diff --git a/packages/roosterjs-content-model-dom/lib/index.ts b/packages/roosterjs-content-model-dom/lib/index.ts
index d57626c233c..3b4dc813935 100644
--- a/packages/roosterjs-content-model-dom/lib/index.ts
+++ b/packages/roosterjs-content-model-dom/lib/index.ts
@@ -155,3 +155,4 @@ export { NumberingListType } from './constants/NumberingListType';
 export { TableBorderFormat } from './constants/TableBorderFormat';
 export { OrderedListStyleMap } from './constants/OrderedListStyleMap';
 export { UnorderedListStyleMap } from './constants/UnorderedListStyleMap';
+export { EmptySegmentFormat } from './constants/EmptySegmentFormat';
diff --git a/packages/roosterjs-content-model-dom/lib/modelApi/editing/mergeModel.ts b/packages/roosterjs-content-model-dom/lib/modelApi/editing/mergeModel.ts
index 94ed4f65319..dfdc35ed0a6 100644
--- a/packages/roosterjs-content-model-dom/lib/modelApi/editing/mergeModel.ts
+++ b/packages/roosterjs-content-model-dom/lib/modelApi/editing/mergeModel.ts
@@ -5,6 +5,7 @@ import { createParagraph } from '../creators/createParagraph';
 import { createSelectionMarker } from '../creators/createSelectionMarker';
 import { createTableCell } from '../creators/createTableCell';
 import { deleteSelection } from './deleteSelection';
+import { EmptySegmentFormat } from '../../constants/EmptySegmentFormat';
 import { getClosestAncestorBlockGroupIndex } from './getClosestAncestorBlockGroupIndex';
 import { getObjectKeys } from '../..//domUtils/getObjectKeys';
 import { mutateBlock } from '../common/mutate';
@@ -29,21 +30,7 @@ import type {
 } from 'roosterjs-content-model-types';
 
 const HeadingTags = ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'];
-// An object to provide keys of required properties of segment format, do NOT use any of its values
-const RequiredEmptySegmentFormat: Required<ContentModelSegmentFormat> = {
-    backgroundColor: null!,
-    fontFamily: null!,
-    fontSize: null!,
-    fontWeight: null!,
-    italic: null!,
-    letterSpacing: null!,
-    lineHeight: null!,
-    strikethrough: null!,
-    superOrSubScriptSequence: null!,
-    textColor: null!,
-    underline: null!,
-};
-const KeysOfSegmentFormat = getObjectKeys(RequiredEmptySegmentFormat);
+const KeysOfSegmentFormat = getObjectKeys(EmptySegmentFormat);
 
 /**
  * Merge source model into target mode