loadAsObj method
Same as load, but expects the file to be a Map<String, dynamic> representing a single object. Will fail if it's not a map. It may return null.
Implementation
Future<Map<String, dynamic>?> loadAsObj() async {
Object? simpleObj = await load();
if (simpleObj == null) return null;
if (simpleObj is! Map<String, dynamic>) throw PersistException("Not an object: $simpleObj");
return simpleObj;
}