saveAndUpdate method

Future<E> saveAndUpdate(
  1. E handle(
    1. E? oldValue
    ), [
  2. String key = 'default',
  3. E? defaultValue
])

Implementation

Future<E> saveAndUpdate(E Function(E? oldValue) handle , [String key = 'default',E? defaultValue]) async {
  final oldV = await getValue(key,defaultValue: defaultValue);
  final newV = handle.call(oldV);
  await setValue(key, newV);
  return newV;
}