> For the complete documentation index, see [llms.txt](https://helio-junior.gitbook.io/vuex4flutter/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://helio-junior.gitbook.io/vuex4flutter/the-store/mutations.md).

# Mutations

## Defining a mutation

```dart
class UpdateMessageMutation extends Mutation {
  @override
  String get name => 'changeMessage'; // if you don't override it will be the name of class: 'UpdateMessageMutation' 

  @override
  void call(Map<String, dynamic> state, payload) {
    state['message'] = payload;
  }
}
```

{% hint style="warning" %}
All mutations should be sync, if you need to perform async operations you must use an action
{% endhint %}

## Registering the mutation on Store

```dart
class MyStore extends Store {
  MyStore() : super(
    Module(
      state: {
        'message': 'A message',
      },
      mutations: [
        UpdateMessageMutation(),
      ],
    ),
  );
}
```

## Commiting a change

```dart
store.commit('/changeMessage', 'New message');
```


---

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