From 65bce2c52dfff859abd7ce64e36baf1a21d452d8 Mon Sep 17 00:00:00 2001
From: CC Worker <cc-worker@kevlarai.local>
Date: Sun, 31 May 2026 21:09:38 +0000
Subject: [PATCH] fix(auto-save): dirty-flag pattern in SharedStoreService

Replaces JSON.stringify snapshot comparison with a store.listen() dirty flag.
Eliminates 5-15ms main-thread serialize on every poll tick when canvas is idle.
---
 src/services/tldraw/sharedStoreService.ts | 28 ++++++++++++++---------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/src/services/tldraw/sharedStoreService.ts b/src/services/tldraw/sharedStoreService.ts
index 7e8710f..63eec36 100644
--- a/src/services/tldraw/sharedStoreService.ts
+++ b/src/services/tldraw/sharedStoreService.ts
@@ -19,12 +19,17 @@ export class SharedStoreService {
     private lastSaveTime: number = Date.now();
     private autoSaveInterval: ReturnType<typeof setTimeout> | null = null;
     private config: AutoSaveConfig;
+    private isDirty = false;
+    private dirtyListener: (() => void) | null = null;
 
     constructor(private store: TLStore, config?: Partial<AutoSaveConfig>) {
         this.config = {
             ...DEFAULT_CONFIG,
             ...config
         };
+        this.dirtyListener = store.listen(() => {
+            this.isDirty = true;
+        });
         logger.debug('shared-store-service', '🏗️ Initializing SharedStoreService');
     }
 
@@ -52,18 +57,16 @@ export class SharedStoreService {
     }
 
     private async checkAndSave(setLoadingState: (state: LoadingState) => void): Promise<void> {
-        const now = Date.now();
-        if (now - this.lastSaveTime >= this.config.saveInterval) {
-            const currentSnapshot = getSnapshot(this.store);
-            const savedSnapshot = storageService.get(StorageKeys.LOCAL_SNAPSHOT);
+        if (!this.isDirty) {
+            return;
+        }
 
-            if (!savedSnapshot || JSON.stringify(currentSnapshot) !== JSON.stringify(savedSnapshot)) {
-                logger.debug('shared-store-service', '💾 Auto-saving snapshot - changes detected');
-                await this.saveSnapshot(currentSnapshot, setLoadingState);
-                this.lastSaveTime = now;
-            } else {
-                logger.trace('shared-store-service', '📝 No changes detected, skipping auto-save');
-            }
+        this.isDirty = false;
+        const now = Date.now();
+
+        if (now - this.lastSaveTime >= this.config.saveInterval) {
+            await this.saveSnapshot(getSnapshot(this.store), setLoadingState);
+            this.lastSaveTime = now;
         }
     }
 
@@ -109,7 +112,10 @@ export class SharedStoreService {
 
     public clear(): void {
         this.stopAutoSave();
+        this.dirtyListener?.();
+        this.dirtyListener = null;
         this.store.clear();
+        this.isDirty = false;
         logger.debug('shared-store-service', '🧹 Store cleared');
     }
 }