fcheck 0.9.15

A CLI tool for analyzing Flutter and Dart code quality, checking project metrics, comment ratios, class organization, hardcoded strings, and source sorting validation.

fCheck

Fast local quality checks for Flutter and Dart projects.

fCheck runs one deterministic analysis pass and reports architecture, maintainability, and safety issues that default lints usually do not cover.

Why fCheck

• Single local run for multiple quality domains
• Deterministic output for CI and code review
• No network calls required
• Console, JSON, and diagram outputs
• Works as both:
  • CLI tool
  • Dart package in your own app/tooling

Checks Included

• code_size
• dead_code
• documentation
• duplicate_code
• hardcoded_strings
• layers
• magic_numbers
• one_class_per_file
• secrets
• source_sorting

Detailed behavior and edge cases are documented in RULES*.md.

Install

Option 1: Global CLI

dart pub global activate fcheck
fcheck .

Option 2: Project Dev Dependency

dart pub add fcheck -d
dart run fcheck .

Option 3: Use as a Dart package in your app/tool

dart pub add fcheck

import 'dart:io';
import 'package:fcheck/fcheck.dart';

void main() {
  final metrics = AnalyzeFolder(Directory('.')).analyze();
  print('Score: ${metrics.complianceScore}%');
}

Quick Start (CLI)

# Analyze current folder
fcheck .

# Analyze another folder
fcheck ../my_app
fcheck --input ../my_app

# JSON output
fcheck --json

# Full list output
fcheck --list full

# Generate diagrams
fcheck --svg --svgfolder --svgsize --mermaid --plantuml

# Auto-fix source sorting issues
fcheck --fix

If installed as a dev dependency, prefix commands with dart run.

Configuration (.fcheck)

Create .fcheck in the input directory (--input) or current directory.

input:
  root: app
  exclude:
    - "**/generated/**"
    - "**/*.g.dart"

analyzers:
  default: on
  disabled:
    - hardcoded_strings
    - source_sorting
  options:
    duplicate_code:
      similarity_threshold: 0.85 # 0.0..1.0
      min_tokens: 20
      min_non_empty_lines: 10
    code_size:
      max_file_loc: 900
      max_class_loc: 800
      max_function_loc: 700
      max_method_loc: 500

Notes:

• analyzers.default accepts on|off and true|false
• Opt-in mode:

analyzers:
  default: off
  enabled:
    - magic_numbers
    - secrets

• Config precedence: built-in defaults < .fcheck < CLI flags
• input.root is resolved relative to the .fcheck file location
• --exclude adds patterns on top of .fcheck input.exclude

Legacy compatibility is supported:

ignores:
  hardcoded_strings: true
  layers: true
  magic_numbers: true

Ignore Directives

Use top-of-file or line-level ignore directives:

// ignore: fcheck_dead_code
// ignore: fcheck_documentation
// ignore: fcheck_duplicate_code
// ignore: fcheck_hardcoded_strings
// ignore_for_file: avoid_hardcoded_strings_in_widgets
// ignore: fcheck_layers
// ignore: fcheck_magic_numbers
// ignore: fcheck_one_class_per_file
// ignore: fcheck_secrets

For generated guidance:

fcheck --help-ignore

Visual Outputs

fcheck --svg        # layers.svg
fcheck --svgfolder  # layers_folders.svg
fcheck --svgsize    # fcheck_code_size.svg
fcheck --mermaid    # layers.mmd
fcheck --plantuml   # layers.puml

Layers Files diagram:

Layers Folder diagram:

Code size diagram:

Exclusions

# Add custom excludes
fcheck --exclude "**/generated/**" --exclude "**/*.g.dart"

# Inspect excluded items
fcheck --excluded
fcheck --excluded --json

Default exclusion behavior includes hidden folders and common non-analysis directories (.git, .dart_tool, build, example, test, platform folders, etc.).

CI Example (GitHub Actions)

name: fcheck
on:
  pull_request:
  push:
    branches: [main]

jobs:
  quality:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: dart-lang/setup-dart@v1
      - run: dart pub global activate fcheck
      - run: dart pub global run fcheck --json > fcheck-report.json
      - uses: actions/upload-artifact@v4
        with:
          name: fcheck-report
          path: fcheck-report.json

Contributing

1. Fork the repo
2. Create a branch
3. Implement changes
4. Run ./tool/check.sh
5. Open a pull request

License

MIT