From 67a695bb336f53e0b7356149b950f49a6f8654c2 Mon Sep 17 00:00:00 2001
From: Joe Anderson <joe@mousetrapped.co.uk>
Date: Sun, 18 Feb 2024 21:52:43 +0000
Subject: [PATCH 1/2] Fix StringCharMapping key order dependency

---
 .changeset/great-buses-switch.md              |  5 +++
 .../utils/string-char-mapping.spec.ts         | 10 ++++++
 .../src/internal/utils/string-char-mapping.ts | 35 ++++++++-----------
 3 files changed, 29 insertions(+), 21 deletions(-)
 create mode 100644 .changeset/great-buses-switch.md
 create mode 100644 packages/diff/src/internal/utils/string-char-mapping.spec.ts

diff --git a/.changeset/great-buses-switch.md b/.changeset/great-buses-switch.md
new file mode 100644
index 0000000000..e446aa546f
--- /dev/null
+++ b/.changeset/great-buses-switch.md
@@ -0,0 +1,5 @@
+---
+"@udecode/plate-diff": patch
+---
+
+Fix: Node equivalency checking is incorrectly dependent on the key order of the node object
diff --git a/packages/diff/src/internal/utils/string-char-mapping.spec.ts b/packages/diff/src/internal/utils/string-char-mapping.spec.ts
new file mode 100644
index 0000000000..baee45458d
--- /dev/null
+++ b/packages/diff/src/internal/utils/string-char-mapping.spec.ts
@@ -0,0 +1,10 @@
+import { StringCharMapping } from './string-char-mapping';
+
+describe('StringCharMapping', () => {
+  it('treats nodes as equivalent regardless of key order', () => {
+    const map = new StringCharMapping();
+    const c1 = map.nodeToChar({ type: 'a', children: [] });
+    const c2 = map.nodeToChar({ children: [], type: 'a' });
+    expect(c1).toBe(c2);
+  });
+});
diff --git a/packages/diff/src/internal/utils/string-char-mapping.ts b/packages/diff/src/internal/utils/string-char-mapping.ts
index 48738fc5ad..7ee7f6cd07 100644
--- a/packages/diff/src/internal/utils/string-char-mapping.ts
+++ b/packages/diff/src/internal/utils/string-char-mapping.ts
@@ -4,27 +4,30 @@
  */
 
 import { TDescendant } from '@udecode/plate-common';
+import isEqual from 'lodash/isEqual.js';
+
+import { unusedCharGenerator } from './unused-char-generator';
 
 export class StringCharMapping {
-  private _nextChar: string = 'A';
+  private _charGenerator = unusedCharGenerator();
   private _charToNode: Map<string, TDescendant> = new Map();
-  private _keyToChar: Map<string, string> = new Map();
+  private _mappedNodes: [TDescendant, string][] = [];
 
   public nodesToString(nodes: TDescendant[]): string {
     return nodes.map(this.nodeToChar.bind(this)).join('');
   }
 
   public nodeToChar(node: TDescendant): string {
-    const key = this.getKeyForNode(node);
-
-    const existingChar = this._keyToChar.get(key);
-    if (existingChar) return existingChar;
-
-    const c = this.getNextChar();
-
-    this._keyToChar.set(key, c);
+    // Check for a previously assigned character
+    for (const [n, c] of this._mappedNodes) {
+      if (isEqual(n, node)) {
+        return c;
+      }
+    }
+
+    const c = this._charGenerator.next().value;
+    this._mappedNodes.push([node, c]);
     this._charToNode.set(c, node);
-
     return c;
   }
 
@@ -37,14 +40,4 @@ export class StringCharMapping {
     if (!node) throw new Error(`No node found for char ${c}`);
     return node;
   }
-
-  private getKeyForNode(node: TDescendant): string {
-    return JSON.stringify(node);
-  }
-
-  private getNextChar(): string {
-    const c = this._nextChar;
-    this._nextChar = String.fromCodePoint(this._nextChar.codePointAt(0)! + 1);
-    return c;
-  }
 }

From d523a071292ebfd3627c20c62b148fff9d6d0d2f Mon Sep 17 00:00:00 2001
From: Joe Anderson <joe@mousetrapped.co.uk>
Date: Sun, 18 Feb 2024 21:57:09 +0000
Subject: [PATCH 2/2] Remove duplicated data on StringCharMapping

---
 packages/diff/src/internal/utils/string-char-mapping.ts | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/packages/diff/src/internal/utils/string-char-mapping.ts b/packages/diff/src/internal/utils/string-char-mapping.ts
index 7ee7f6cd07..791a8ce066 100644
--- a/packages/diff/src/internal/utils/string-char-mapping.ts
+++ b/packages/diff/src/internal/utils/string-char-mapping.ts
@@ -10,7 +10,6 @@ import { unusedCharGenerator } from './unused-char-generator';
 
 export class StringCharMapping {
   private _charGenerator = unusedCharGenerator();
-  private _charToNode: Map<string, TDescendant> = new Map();
   private _mappedNodes: [TDescendant, string][] = [];
 
   public nodesToString(nodes: TDescendant[]): string {
@@ -27,7 +26,6 @@ export class StringCharMapping {
 
     const c = this._charGenerator.next().value;
     this._mappedNodes.push([node, c]);
-    this._charToNode.set(c, node);
     return c;
   }
 
@@ -36,8 +34,8 @@ export class StringCharMapping {
   }
 
   public charToNode(c: string): TDescendant {
-    const node = this._charToNode.get(c);
-    if (!node) throw new Error(`No node found for char ${c}`);
-    return node;
+    const entry = this._mappedNodes.find(([_node, c2]) => c2 === c);
+    if (!entry) throw new Error(`No node found for char ${c}`);
+    return entry[0];
   }
 }