Proper way to deduplicate code in 2 providers

[vware]

Assume I have the providers below. I had the like/unlike code in an extension, which was working well. But I am trying to add optimistic updates, which kinda broke my extension-based approach, since I was unable to modify the state in my extension methods. Below code works fine (updates UI immediately, and then refreshes state from the server), but is obviously undesirable.

Obviously, the list updating could be extracted for each class, but that's not my issue... :) Is there some better way to do this? Sorry, might be obvious, but I really am not good enough to find a proper solution for this...

@riverpod
class Provider1 extends _$Provider1 {
  @override
  build...

  Future<void> like(int id) async {
    if (state.value != null) {
      final updatedList = state.value!.map((post) {
        if (post.id == id) {
          return post.copyWith(isLiking: true);
        }
        return post;
      }).toList();
      state = AsyncData(updatedList);
    }

    await MyApi.likePost(id);
    ref.invalidateSelf();
  }

  Future<void> unlike(int id) async {
    if (state.value != null) {
      final updatedList = state.value!.map((post) {
        if (post.id == id) {
          return post.copyWith(isLiking: false);
        }
        return post;
      }).toList();
      state = AsyncData(updatedList);
    }

    await MyApi.unlikePost(id);
    ref.invalidateSelf();
  }
}

@riverpod
class Provider2 extends _$Provider2 {
  @override
  build...

  Future<void> like(int id) async {
    if (state.value != null) {
      final updatedList = state.value!.map((post) {
        if (post.id == id) {
          return post.copyWith(isLiking: true);
        }
        return post;
      }).toList();
      state = AsyncData(updatedList);
    }

    await MyApi.likePost(id);
    ref.invalidateSelf();
  }

  Future<void> unlike(int id) async {
    if (state.value != null) {
      final updatedList = state.value!.map((post) {
        if (post.id == id) {
          return post.copyWith(isLiking: false);
        }
        return post;
      }).toList();
      state = AsyncData(updatedList);
    }

    await MyApi.unlikePost(id);
    ref.invalidateSelf();
  }
}