Add editor-autosave.ts for autosave functionality

src/serialization/editor-autosave.ts

@@ -0,0 +1,52 @@
+import type { SaveSceneDocumentDraftResult } from "./local-draft-storage";
+
+export interface EditorAutosaveControllerOptions {
+  debounceMs?: number;
+  onComplete?: (result: SaveSceneDocumentDraftResult) => void;
+  saveDraft: () => SaveSceneDocumentDraftResult;
+}
+
+export class EditorAutosaveController {
+  private readonly debounceMs: number;
+  private readonly onComplete: ((result: SaveSceneDocumentDraftResult) => void) | undefined;
+  private readonly saveDraft: () => SaveSceneDocumentDraftResult;
+  private timeoutId: number | null = null;
+
+  constructor(options: EditorAutosaveControllerOptions) {
+    this.debounceMs = options.debounceMs ?? 200;
+    this.onComplete = options.onComplete;
+    this.saveDraft = options.saveDraft;
+  }
+
+  schedule() {
+    this.clearPendingTimeout();
+    this.timeoutId = window.setTimeout(() => {
+      this.timeoutId = null;
+      this.runSave();
+    }, this.debounceMs);
+  }
+
+  flush(): SaveSceneDocumentDraftResult {
+    this.clearPendingTimeout();
+    return this.runSave();
+  }
+
+  dispose() {
+    this.clearPendingTimeout();
+  }
+
+  private clearPendingTimeout() {
+    if (this.timeoutId === null) {
+      return;
+    }
+
+    window.clearTimeout(this.timeoutId);
+    this.timeoutId = null;
+  }
+
+  private runSave(): SaveSceneDocumentDraftResult {
+    const result = this.saveDraft();
+    this.onComplete?.(result);
+    return result;
+  }
+}