1 files changed, 23 insertions, 0 deletions
diff --git a/apps/web/src/commands/preview-tracker.ts b/apps/web/src/commands/preview-tracker.ts
new file mode 100644
index 00000000..68c8dee3
--- /dev/null
+++ b/apps/web/src/commands/preview-tracker.ts
@@ -0,0 +1,23 @@
+export class PreviewTracker<T> {
+	private snapshot: T | null = null;
+
+	begin({ state }: { state: T }): void {
+		if (this.snapshot === null) {
+			this.snapshot = structuredClone(state);
+		}
+	}
+
+	isActive(): boolean {
+		return this.snapshot !== null;
+	}
+
+	getSnapshot(): T | null {
+		return this.snapshot;
+	}
+
+	end(): T | null {
+		const snapshot = this.snapshot;
+		this.snapshot = null;
+		return snapshot;
+	}
+}