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Check Unused Code

Checks unused classes, functions, top level variables, extensions, enums, mixins and type aliases.

info

This implementation doesn't check for particular class members (fields / properties / methods) usage. If you need this functionality, refer to check-unused-code command for Teams version.

To execute the command, run:

$ flutter pub run dart_code_metrics:metrics check-unused-code lib

Full command description:

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


-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-]monorepo                               Treat all exported code as unused by default.


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

Suppressing the command​

In order to suppress the command add the ignore: unused-code comment. To suppress for an entire file add ignore_for_file: unused-code to the beginning of a file.

Monorepo support​

By default the command treats all code that is exported from the package as used. To disable this behavior use --monorepo flag. This might be useful when all the packages in your repository are only used within the repository and are not published to the pub.

Output example​

Console​

Use --reporter=console to enable this format.

Console

JSON​

The reporter prints a single JSON object containing meta information and the unused code 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
  • unusedCode - an array of unused code issues
{
  "formatVersion": 2,
  "timestamp": "2021-04-11 14:44:42",
  "unusedCode": [
    {
      ...
    },
    {
      ...
    },
    {
      ...
    }
  ]
}

The unusedCode object fields are​

  • path - a relative path of the unused file
  • issues - an array of issues detected in the target file
{
  "path": "lib/src/some/file.dart",
  "issues": [
    ...
  ],
}

The issue object fields are​

  • declarationType - unused declaration type
  • declarationName - unused declaration 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
{
  "declarationType": "extension",
  "declarationName": "StringX",
  "offset": 156,
  "line": 7,
  "column": 1
}