whereKeyStartsWithOrFail method
Implementation
@override
Map<String, dynamic> whereKeyStartsWithOrFail(String prefix,
{Exception Function()? onFail}) {
final entries = _storage.entries
.where((element) => element.key.startsWith(prefix))
.fold(<String, dynamic>{},
(acc, element) => {...acc, element.key: element.value});
return entries.isEmpty
? onFail != null
? throw onFail()
: throw Exception('No keys found')
: entries;
}