commit | 49832b60c5b862240741d9f2c2a0e520f47f8606 | [log] [tgz] |
---|---|---|
author | Bob Nystrom <rnystrom@google.com> | Wed Sep 11 14:10:24 2024 -0700 |
committer | GitHub <noreply@github.com> | Wed Sep 11 14:10:24 2024 -0700 |
tree | d5d27571d9e52df332a6a11563f70254ce942bbf | |
parent | 87e527ddbd60b0b8a4f7519785e0ed743e2b0a25 [diff] |
Remove the old CLI options and executables. (#1565) Before the `dart format` command was added to the core Dart SDK, users accessed the formatter by running a separate `dartfmt` executable that was included with the Dart SDK. That executable had a different CLI interface. For example, you had to pass `-w` to get it to overwrite files and if you passed no arguments at all, it silently sat there waiting for input on stdin. When we added `dart format`, we took that opportunity to revamp the CLI options. However, the dart_style package still exposed an executable with the old CLI. If you ran `dart pub global activate dart_style`, this would give you a `dartfmt` (and `dartformat`) executable with the old CLI options. Now that almost everyone is using `dart format`, we have removed the old CLI and the old package executables. You can still run the formatter on the CLI through the package (for example, if you want to use a particular version of dart_style instead of the one bundled with your Dart SDK). But it now uses the exact same CLI options and arguments as the `dart format` command. You can invoke it with `dart run dart_style:format <args...>`.
The dart_style package defines an automatic, opinionated formatter for Dart code. It replaces the whitespace in your program with what it deems to be the best formatting for it. Resulting code should follow the Dart style guide but, moreso, should look nice to most human readers, most of the time.
The formatter handles indentation, inline whitespace, and (by far the most difficult) intelligent line wrapping. It has no problems with nested collections, function expressions, long argument lists, or otherwise tricky code.
The formatter turns code like this:
// BEFORE formatting if (tag=='style'||tag=='script'&&(type==null||type == TYPE_JS ||type==TYPE_DART)|| tag=='link'&&(rel=='stylesheet'||rel=='import')) {}
into:
// AFTER formatting if (tag == 'style' || tag == 'script' && (type == null || type == TYPE_JS || type == TYPE_DART) || tag == 'link' && (rel == 'stylesheet' || rel == 'import')) {}
The formatter will never break your code—you can safely invoke it automatically from build and presubmit scripts.
The formatter is part of the unified dart
developer tool included in the Dart SDK, so most users get it directly from there. That has the latest version of the formatter that was available when the SDK was released.
IDEs and editors that support Dart usually provide easy ways to run the formatter. For example, in WebStorm you can right-click a .dart file and then choose Reformat with Dart Style.
Here's a simple example of using the formatter on the command line:
$ dart format test.dart
This command formats the test.dart
file and writes the result to the file.
dart format
takes a list of paths, which can point to directories or files. If the path is a directory, it processes every .dart
file in that directory or any of its subdirectories.
By default, it formats each file and write the formatting changes to the files. If you pass --output show
, it prints the formatted code to stdout.
You may pass a -l
option to control the width of the page that it wraps lines to fit within, but you're strongly encouraged to keep the default line length of 80 columns.
If you want to use the formatter in something like a presubmit script or commit hook, you can pass flags to omit writing formatting changes to disk and to update the exit code to indicate success/failure:
$ dart format --output=none --set-exit-if-changed .
If you need to run a different version of the formatter, you can globally activate the package from the dart_style package on pub.dev:
$ pub global activate dart_style $ pub global run dart_style:format ...
The package also exposes a single dart_style library containing a programmatic API for formatting code. Simple usage looks like this:
import 'package:dart_style/dart_style.dart'; main() { final formatter = DartFormatter(); try { print(formatter.format(""" library an_entire_compilation_unit; class SomeClass {} """)); print(formatter.formatStatement("aSingle(statement);")); } on FormatterException catch (ex) { print(ex); } }
Before sending an email, see if you are asking a frequently asked question.
Before filing a bug, or if you want to understand how work on the formatter is managed, see how we track issues.