Always have a trailing comma on enums

[spydon]

What input code did you provide to the formatter?

enum Conferences {
  FlutterAndFriends,
  FlutterLatAm,
  FlutterCon,
  FlutterVikings,
}

What output did the formatter produce?

enum Conferences { FlutterAndFriends, FlutterLatAm, FlutterCon, FlutterVikings }

What output did you expect or want the formatter to produce?

Describe how you expected the formatter to format the code, ideally by showing what you had in mind as code.

enum Conferences {
  FlutterAndFriends,
  FlutterLatAm,
  FlutterCon,
  FlutterVikings,
}

Anything else we should know?

Some formatters are forcing trailing commas on enums (like Prettier, thanks for the reference Bob!), and I think we should do the same.

Here are some reasons why I think this would be a good idea:

1. Cleaner Diffs in Version Control
2. Easier Reordering
3. Simplifies Adding/Removing Items
4. Improves Readability

[b2nkuu]

it's effort form formatter SDK version 3.7.X
You can avoid effect to downgrade SDK in pubspec.yaml to ^3.6.X (ex, ^3.6.1)

Hope this helps.

[spydon]

@b2nkuu this issue is about changing the behavior of the new formatter, hence downgrading the SDK to use the old formatter is not a solution.

[b2nkuu]

@spydon

Oh, i see something

You can set to preserve trailing_commas at analysis_options.yaml

analysis_options.yaml
include: package:flutter_lints/flutter.yaml

formatter:
  trailing_commas: preserve

It's work ✨✨

[spydon]

@b2nkuu I know, but this issue is not about work-arounds, it is about changing the default behavior of the formatter for enums.

[b2nkuu]

oh, i mistake it, sorry about that.

[filiph]

Sorry for the duplicate issue (#1730). I completely agree with @spydon here.

I do think an exception for very tiny enums could work, something like this:

enum Result { ok, failure }

That is to say, if the enum body is just the enum values, and it's below a certain threshold of length (e.g. 20 chars), then it's okay to have it on one line. But as soon as there are more values, or they are longer, or there is anything at all except the values inside the body of the enum, then each value should be on its own line.

That said, I'm also fine with just having all enums — including the tiny ones — be in tall style since that's probably easier to reason about and implement.