add visit function for snapshot

src/index.ts

@@ -1,4 +1,8 @@
-import snapshot, { serializeNodeWithId, transformAttribute } from './snapshot';
+import snapshot, {
+  serializeNodeWithId,
+  transformAttribute,
+  visit,
+} from './snapshot';
 import rebuild, { buildNodeWithSN, addHoverClass } from './rebuild';
 export * from './types';
 
@@ -9,4 +13,5 @@ export {
   buildNodeWithSN,
   addHoverClass,
   transformAttribute,
+  visit,
 };