Check unused l10n

Checks unused Dart class members, that encapsulates the app’s localized values.

An example of such class:

class ClassWithLocalization {
  String get title {
    return Intl.message(
      'Hello World',
      name: 'title',
      desc: 'Title for the Demo application',
      locale: localeName,
    );
  }
}

Read more about this localization approach in the Flutter docs.

By default the command searches for classes that end with I18n, but you can override this behavior with --class-pattern argument.

To execute the command, run

$ dart run flutterando_metrics:metrics check-unused-l10n lib

# or for a Flutter package
$ flutter pub run flutterando_metrics:metrics check-unused-l10n lib

Full command description:

Usage: metrics check-unused-l10n [arguments] <directories>
-h, --help                                       Print this usage information.


-p, --class-pattern=<I18n$>                      The pattern to detect classes providing localization
                                                 (defaults to "I18n$")


-r, --reporter=<console>                         The format of the output of the analysis.
                                                 [console (default), json]
    --report-to-file=<path/to/report.json>       The path, where a JSON file with the analysis result will be placed (only for the JSON reporter).

-c, --print-config                               Print resolved config.


    --root-folder=<./>                           Root folder.
                                                 (defaults to current directory)
    --sdk-path=<directory-path>                  Dart SDK directory path.
                                                 Should be provided only when you run the application as compiled executable(https://dart.dev/tools/dart-compile#exe) and automatic Dart SDK path detection fails.
    --exclude=<{/**.g.dart,/**.freezed.dart}>    File paths in Glob syntax to be exclude.
                                                 (defaults to "{/**.g.dart,/**.freezed.dart}")


    --no-congratulate                            Don't show output even when there are no issues.


    --[no-]fatal-unused                          Treat find unused l10n as fatal.

Output example

Console

Use --reporter=console to enable this format.

JSON

The reporter prints a single JSON object containing meta information and the unused file paths. Use --reporter=json to enable this format.

The root object fields are

• formatVersion - an integer representing the format version (will be incremented each time the serialization format changes)
• timestamp - a creation time of the report in YYYY-MM-DD HH:MM:SS format
• unusedLocalizations - an array of unused files

{
  "formatVersion": 2,
  "timestamp": "2021-04-11 14:44:42",
  "unusedLocalizations": [
    {
      ...
    },
    {
      ...
    },
    {
      ...
    }
  ]
}

The unusedLocalizations object fields are

• path - a relative path of the unused file
• className - a name of the class that has unused members
• issues - an array of issues detected in the target class

{
  "path": "lib/src/some/class.dart",
  "className": "class",
  "issues": [
    ...
  ],
}

The issue object fields are

• memberName - unused class member name
• offset - a zero-based offset of the class member location in the source
• line - a zero-based line of the class member location in the source
• column - a zero-based column of class member the location in the source

{
  "memberName": "someGetter",
  "offset": 156,
  "line": 7,
  "column": 1
}