From 0b435cb094567b2150de9d02df4c1af9926ba1f8 Mon Sep 17 00:00:00 2001
From: Zihua Li <i@zihua.li>
Date: Thu, 1 Jun 2023 22:08:49 +0800
Subject: [PATCH] Fix embed inherits formats unexpectedly

---
 core/editor.ts           |  3 +++
 test/unit/core/editor.js | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/core/editor.ts b/core/editor.ts
index 0b7e8c4aee..5b4b6a9a49 100644
--- a/core/editor.ts
+++ b/core/editor.ts
@@ -62,6 +62,9 @@ class Editor {
             ) {
               isImplicitNewlineAppended = true;
             }
+            const [leaf] = this.scroll.leaf(index);
+            const formats = merge({}, bubbleFormats(leaf));
+            attributes = AttributeMap.diff(formats, attributes) || {};
           } else if (index > 0) {
             // @ts-expect-error
             const [leaf, offset] = this.scroll.descendant(LeafBlot, index - 1);
diff --git a/test/unit/core/editor.js b/test/unit/core/editor.js
index 162865c63a..542c896063 100644
--- a/test/unit/core/editor.js
+++ b/test/unit/core/editor.js
@@ -517,6 +517,16 @@ describe('Editor', function () {
       );
     });
 
+    it('insert inline embed to the middle of formatted content', function () {
+      const editor = this.initialize(Editor, '<p><strong>0123</strong></p>');
+      editor.applyDelta(
+        new Delta().retain(2).insert({ image: '/assets/favicon.png' }),
+      );
+      expect(this.container).toEqualHTML(
+        '<p><strong>01</strong><img src="/assets/favicon.png"><strong>23</strong></p>',
+      );
+    });
+
     it('insert block embed with delete before block embed', function () {
       const editor = this.initialize(
         Editor,