updateWithUndo method

void updateWithUndo(T reducer(T state), { JIntent<JState>? origin, })

Applies a reducer and records the previous state only for a real change. Equal states, throwing reducers, cancellation and disposal leave history untouched. When recording is disabled this behaves like update.

Implementation

void updateWithUndo(T Function(T state) reducer, {JIntent? origin}) {
  if (!_canChangeHistory) return;
  if (!_undoRedoEnabled || _isUndoRedoOperation) {
    update(reducer, origin: origin);
    return;
  }
  try {
    update((previous) {
      final next = reducer(previous);
      if (mounted && previous != next) {
        _undoStack.add(previous);
        if (_undoStack.length > _maxHistorySize) _undoStack.removeAt(0);
        _redoStack.clear();
      }
      return next;
    }, origin: origin);
  } finally {
    _publishHistory();
  }
}