feat(vscode): add useUnionTypes setting

[zbarbuto]

Status

READY

Breaking Changes

NO

Description

Adds a new useUnionTypes setting to both newBlocTemplate and newCubitTemplate. Defaults to true to backwards compatibility. When turned off, state classes will be generated as a single freezed class rather than using unions.

Also brings support for the existing useSealedClasses to freezed state generation. I'm happy to remove this from the change set if you'd prefer not changing two things in the same PR but it did seem harmless enough...

Example class generated with the setting as true (the default)

part of 'foo_cubit.dart';

@freezed
sealed class FooState with _$FooState {
  const factory FooState.initial() = _Initial;
}

Example class generated with the setting as false

part of 'foo_bloc.dart';

@freezed
sealed class FooState with _$FooState {
  const factory FooState() = _FooState;
}

This is useful if you prefer states that can rely solely on the copyWith generated from freezed to emit state changes. For example:

@freezed
sealed class CounterState with _$CounterState {
  const factory CounterState({ required int count }) = _CounterState;
}

No need for an initial state here and for changes we can just use emit(state.copyWith( count: state.count + 1 )).

Or if you prefer to maintain existing data between states:

@freezed
sealed class TodoState with _$TodoState {
  const factory TodoState({ required bool isLoading, List<Todo>? data }) = _TodoState;
}

Here, we can trigger loading without emitting a TodoState.loading() which would lost our current data with emit(state.copyWith( loading: true )).

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore

[felangel]

Thanks so much for the contribution! I think we'll likely want this setting to apply to the other templates as well (not just freezed).

I'll take a closer look shortly, apologies for the delay!

[zbarbuto]

Thanks for taking a look @felangel

So basically all the templates like this:

@immutable
${classPrefix} class ${pascalCaseBlocName}State {}

${subclassPrefix}class ${pascalCaseBlocName}Initial extends ${pascalCaseBlocName}State {}

should omit the Initial version class if useSealedClasses is off and just be the first 2 lines?