Formatter for Flutter (or, tree-aware code)

[sethladd]

dartfmt is a really great utility, but it doesn't know about code that is trying to represent a tree. Which, is what Flutter does a lot of :)

We would like an automatic formatter that knows that Flutter code has a lot of tree-like structures, and retains a formatting style that makes tree-like structures easy to read.

Ideally, we'd then use this formatter in our CLI and Atom tools.

[eseidelGoogle]

@Hixie do you have a list/doc of specific wishes for a Flutter formatter?

[Hixie]

I think dart-lang/dart_style#442 is the main list right now.

[sethladd]

See also #4509 which talks about formatting the codelab.

[Hixie]

@abarth is the work you did on this available?

[abarth]

Yep: https://github.com/flutter/flutter_format

[eseidelGoogle]

Note that these days dart-fmt supports trailing commas which has answered at least the most common complaint from Flutter customers, e.g.

return new MyWidget(
  foo: foo,
  bar: bar, // This trailing comma causes dart-fmt not to collapse this into one line.
);

[HansMuller]

Does dart-fmt DTRT with if then statements that lack curly braces?

if (foo)
  bar();

I count over 9000 occurrences of this in our repo, about 1800 in packages/flutter.

[Hixie]

It does something that IMHO is less readable than our style. (removes the newline and wraps)