Dart Imutable map

main.dart

void main() {
  Map groceries = {
    'fruit': ['apple', 'orange', 'grapes'],
    'vegetable': [],
  };

  Map addVegetable = Map()
    ..addAll(groceries)
    ..putIfAbsent('vegetable', () => ['carrot', 'tomato'])
    ..update('vegetable', (_) => ['carrot']);

  print(addVegetable);

}