transformDataState method

void transformDataState(T? transformer(T? data))

Transforms the data within the current success state using the provided transformer function and notifies listeners.

If the current state is not a success state, or if the current data is null and the transformer cannot handle null, the behavior might lead to unexpected states or errors depending on the transformer's implementation. It's generally expected that this method is called when _state.data is valid or the transformer can gracefully handle null.

The transformer function receives the current data T? (which might be null if the state was AsyncState.success(null) or if T is nullable) and should return the new data T. The state will then be updated to AsyncState.success with this new data.

After the transformation, listeners are notified.

Example:

    // Assuming T is List<String> and _state is AsyncState.success(["apple"])
    // Add an item to the list
    transformDataState((currentData) {
      return [...?currentData, "banana"];
    });
    // _state is now AsyncState.success(["apple", "banana"]) and listeners are notified.

    // If T is int and _state is AsyncState.success(5)
    transformDataState((currentData) => (currentData ?? 0) + 1);
    // _state is now AsyncState.success(6)

• Parameter transformer: A function that takes the current data T? from a success state and returns the new data T.

Implementation

void transformDataState(T? Function(T? data) transformer) {
  final transformData = transformer(_state.data);

  if (transformData != null) {
    updateState(transformData);
  } else {
    assert(() {
      if (!ReactiveNotifier.debugLogging) return true;
      log(
        '⚠️ transformDataState<${T.toString()}> returned null - transformation ignored',
      );
      return true;
    }());
  }
}