Dart code metrics

Dart code metrics is a static analysis tool that helps improve code quality. It analyzes code metrics and provides additional rules for dart analyzer. Can be used as a command line tool, analyzer plugin or library.

Reports:

• Cyclomatic complexity of methods
• Lines of Executable Code
• Maximum Nesting
• Number of Arguments
• Number of Methods

Output formats:

• Plain terminal
• GitHub
• Codeclimate
• HTML
• JSON

Usage

Analyzer plugin

A plugin for the Dart analyzer library package providing additional rules from Dart code metrics.

1. Add dependency to pubspec.yaml

   dev_dependencies:
     dart_code_metrics: ^2.4.0

2. Add configuration to analysis_options.yaml

   analyzer:
     plugins:
       - dart_code_metrics
   
   dart_code_metrics:
     anti-patterns:
       - long-method
       - long-parameter-list
     metrics:
       cyclomatic-complexity: 20
       lines-of-executable-code: 50
       number-of-arguments: 4
       maximum-nesting: 5
     metrics-exclude:
       - test/**
     rules:
       - newline-before-return
       - no-boolean-literal-compare
       - no-empty-block
       - prefer-trailing-comma
       - prefer-conditional-expressions
       - no-equal-then-else
   

Command line tool

Simple usage

pub global activate dart_code_metrics
metrics lib

Flutter usage

flutter pub global activate dart_code_metrics
flutter pub global run dart_code_metrics:metrics lib

Full usage

Usage: metrics [options...] <directories>
-h, --help                                             Print this usage information.


-r, --reporter=<console>                               The format of the output of the analysis
                                                       [console (default), github, json, html, codeclimate]
    --verbose                                          Additional flag for Console reporter
    --gitlab                                           Additional flag for Code Climate reporter to report in GitLab Code Quality format


    --cyclomatic-complexity=<20>                       Cyclomatic complexity threshold
    --lines-of-executable-code=<50>                    Lines of executable code threshold
    --number-of-arguments=<4>                          Number of arguments threshold
    --number-of-methods=<10>                           Number of methods threshold
    --maximum-nesting=<5>                              Maximum nesting threshold


    --root-folder=<./>                                 Root folder
                                                       (defaults to current directory)
    --ignore-files=<{/**.g.dart,/**.template.dart}>    Filepaths in Glob syntax to be ignored
                                                       (defaults to "{/**.g.dart,/**.template.dart}")


    --set-exit-on-violation-level=<warning>            Set exit code 2 if code violations same or higher level than selected are detected
                                                       [noted, warning, alarm]

If you want command line tool to check rules, you should add configuration to your analysis_options.yaml as listed in Analyzer plugin usage example.

Library

See example/example.dart

Anti-Patterns

• long-method
• long-parameter-list

Rules

Rules are grouped by category to help you understand their purpose.

Right now auto-fixes are available through an IDE context menu (ex. VS Code Quick Fix).

Common

• avoid-unused-parameters
• binary-expression-operand-order  
• double-literal-format  
• member-ordering  
• newline-before-return
• no-boolean-literal-compare  
• no-empty-block
• no-equal-arguments
• no-equal-then-else
• no-magic-number  
• no-object-declaration
• potential-null-dereference
• prefer-conditional-expressions  
• prefer-trailing-comma-for-collection  
• prefer-trailing-comma    

Intl specific

• prefer-intl-name  
• provide-correct-intl-args

Angular specific

• avoid-preserve-whitespace-false
• component-annotation-arguments-ordering  
• prefer-on-push-cd-strategy

Contributing

If you are interested in contributing, please check out the contribution guidelines. Feedback and contributions are welcome!