From 0d487599ee9a0ad224fd3cd1863a08548096b293 Mon Sep 17 00:00:00 2001
From: Zihua Li <i@zihua.li>
Date: Fri, 10 May 2024 12:09:09 +0800
Subject: [PATCH] Avoid emitting change events for void operations

---
 packages/quill/src/core/editor.ts            |  2 +
 packages/quill/test/fuzz/editor.spec.ts      |  2 +-
 packages/quill/test/unit/core/editor.spec.ts |  7 +++
 packages/quill/test/unit/core/quill.spec.ts  | 52 +++++++++++++++-----
 4 files changed, 49 insertions(+), 14 deletions(-)

diff --git a/packages/quill/src/core/editor.ts b/packages/quill/src/core/editor.ts
index a19485840d..c2a0c3662a 100644
--- a/packages/quill/src/core/editor.ts
+++ b/packages/quill/src/core/editor.ts
@@ -310,6 +310,8 @@ class Editor {
       this.delta = this.getDelta();
       if (!change || !isEqual(oldDelta.compose(change), this.delta)) {
         change = oldDelta.diff(this.delta, selectionInfo);
+      } else if (change) {
+        change = new Delta(change.ops.slice()).chop();
       }
     }
     return change;
diff --git a/packages/quill/test/fuzz/editor.spec.ts b/packages/quill/test/fuzz/editor.spec.ts
index 78f7751dd7..e6389d7f0d 100644
--- a/packages/quill/test/fuzz/editor.spec.ts
+++ b/packages/quill/test/fuzz/editor.spec.ts
@@ -249,7 +249,7 @@ describe('editor', () => {
         const doc = quill.getContents();
         const change = generateChange(doc, randomInt(4) + 1);
         const diff = quill.updateContents(change);
-        expect(change).toEqual(diff);
+        expect(change.chop()).toEqual(diff);
       }
     });
   });
diff --git a/packages/quill/test/unit/core/editor.spec.ts b/packages/quill/test/unit/core/editor.spec.ts
index 0c595332bb..a41bfe3d82 100644
--- a/packages/quill/test/unit/core/editor.spec.ts
+++ b/packages/quill/test/unit/core/editor.spec.ts
@@ -806,6 +806,13 @@ describe('Editor', () => {
     });
   });
 
+  describe('update()', () => {
+    test('chop off void ops', () => {
+      const editor = createEditor('<p><strong>a</strong></p>');
+      expect(editor.update(new Delta().retain(1))).toEqual(new Delta());
+    });
+  });
+
   describe('insertContents', () => {
     const video =
       '<iframe src="#" class="ql-video" frameborder="0" allowfullscreen="true"></iframe>';
diff --git a/packages/quill/test/unit/core/quill.spec.ts b/packages/quill/test/unit/core/quill.spec.ts
index c128c0dc12..c33ac136a4 100644
--- a/packages/quill/test/unit/core/quill.spec.ts
+++ b/packages/quill/test/unit/core/quill.spec.ts
@@ -114,19 +114,45 @@ describe('Quill', () => {
       return { quill, oldDelta };
     };
 
-    test('deleteText()', () => {
-      const { quill, oldDelta } = setup();
-      quill.deleteText(3, 2);
-      const change = new Delta().retain(3).delete(2);
-      expect(quill.root.innerHTML).toMatchInlineSnapshot(
-        '"<p>012<em>5</em>67</p>"',
-      );
-      expect(quill.emitter.emit).toHaveBeenCalledWith(
-        Emitter.events.TEXT_CHANGE,
-        change,
-        oldDelta,
-        Emitter.sources.API,
-      );
+    describe('deleteText()', () => {
+      test('delete text', () => {
+        const { quill, oldDelta } = setup();
+        quill.deleteText(3, 2);
+        const change = new Delta().retain(3).delete(2);
+        expect(quill.root.innerHTML).toMatchInlineSnapshot(
+          '"<p>012<em>5</em>67</p>"',
+        );
+        expect(quill.emitter.emit).toHaveBeenCalledWith(
+          Emitter.events.TEXT_CHANGE,
+          change,
+          oldDelta,
+          Emitter.sources.API,
+        );
+      });
+
+      test('delete 0 length', () => {
+        const { quill } = setup();
+        const delta = quill.deleteText(3, 0);
+        expect(delta).toEqual(new Delta());
+        expect(quill.emitter.emit).not.toHaveBeenCalledWith(
+          Emitter.events.TEXT_CHANGE,
+          expect.anything(),
+          expect.anything(),
+          expect.anything(),
+        );
+      });
+
+      test('delete after trailing', () => {
+        const { quill } = setup();
+        const delta = quill.deleteText(100000, 10);
+        expect(delta).toEqual(new Delta());
+        expect(quill.emitter.emit).not.toHaveBeenCalledWith(
+          Emitter.events.TEXT_CHANGE,
+          expect.anything(),
+          expect.anything(),
+          expect.anything(),
+        );
+      });
     });
 
     test('format()', () => {