wrapReduce method

@protected FutureOr<St?> wrapReduce(Reducer<St> reduce)

You may override wrapReduce to wrap the reduce method and allow for some pre- or post-processing. For example, if you want to prevent an async reducer to change the current state in cases where the current state has already changed since when the reducer started:

Future<St?> wrapReduce(Reducer<St> reduce) async {
   var oldState = state;
   AppState? newState = await reduce();
   return identical(oldState, state) ? newState : null;
};

IMPORTANT:

• Your wrapReduce method MUST always return Future<St?>. If it returns a FutureOr, it will NOT be called, and no error will be shown. This is because AsyncRedux uses the return type to determine if wrapReduce was overridden or not.

• If wrapReduce returns St or St?, an error will be thrown.

• Once you override wrapReduce the action will always be ASYNC, regardless of the before and reduce methods.

See mixins Retry, Throttle, and Debounce for real wrapReduce examples.

Implementation

@protected
FutureOr<St?> wrapReduce(Reducer<St> reduce) {
  return null;
}