sniff-check

Opinionated TypeScript/Next.js Development Toolkit

A comprehensive Rust CLI tool that enforces opinionated code quality standards for TypeScript/Next.js projects. Fast, reliable, and provides actionable feedback to developers.

🔥 Core Philosophy

• Files over 100 lines are considered "smelly code" and should be refactored
• TypeScript 'any' usage is forbidden - strict typing enforced
• Clean separation between utilities and components
• Zero-tolerance for unused imports and dead code
• Comprehensive pre-deployment validation

🚀 Installation

Via npm (Recommended)

# Install globally
npm install -g sniff-check

# Or use with npx (no installation required)
npx sniff-check

# Or install locally in your project
npm install --save-dev sniff-check

Via Cargo (Rust)

# Install from crates.io
cargo install sniff-check

# Or build from source
git clone https://github.com/rizkyviali/sniff-check
cd sniff-check
cargo build --release

Requirements

• Node.js 14+ (for npm installation)
• Rust 1.70+ (for cargo installation or building from source)

📖 Usage

Interactive Menu

sniff
# or
sniff menu

Shows a beautiful terminal menu with all available commands.

Core Commands

🔍 Large Files Detection

sniff large
sniff large --threshold 150  # Custom threshold

Scans all TypeScript/JavaScript files and flags files over the threshold as "smelly code". Provides specific refactoring suggestions based on file type (component, service, API, etc.).

Severity Levels:

• Warning (100-200 lines): Needs attention
• Error (200-400 lines): Should be refactored
• Critical (400+ lines): Must be refactored immediately

📝 TypeScript Quality Check

sniff types

Comprehensive TypeScript analysis:

• Detects 'any' type usage (CRITICAL)
• Finds missing return type annotations
• Identifies @ts-ignore/@ts-expect-error comments
• Calculates type coverage score (0-100%)

🚫 Unused Imports Detection

sniff imports

Smart analysis of import statements:

• Detects unused default, named, and namespace imports
• Handles complex usage patterns (JSX components, type annotations)
• Shows potential bundle size savings
• Supports ES6, CommonJS, and dynamic imports

📦 Bundle Analysis

sniff bundle

Analyzes build output for optimization opportunities:

• Identifies largest chunks and files
• Calculates compression ratios
• Warns about oversized bundles (>2MB total, >500KB per chunk)
• Provides specific optimization recommendations

🚀 Performance Auditing

sniff perf

Comprehensive performance analysis with Lighthouse integration:

• Runs Lighthouse audits on local development servers
• Checks Core Web Vitals (LCP, FID, CLS)
• Analyzes performance, accessibility, best practices, and SEO
• Provides bundle size analysis and optimization recommendations
• Falls back to basic performance checks if Lighthouse unavailable

🧠 Memory Leak Detection

sniff memory

Advanced memory leak pattern detection:

• Scans for common memory leak patterns in TypeScript/JavaScript
• Detects unremoved event listeners, timer leaks, circular references
• Monitors running Node.js processes for high memory usage
• Provides specific cleanup recommendations and best practices

🔧 Environment Validation

sniff env

Complete environment variable validation:

• Checks required environment variables for TypeScript/Next.js projects
• Validates format for URLs, database connections, and Node environments
• Scans .env files for security issues and sensitive data exposure
• Provides environment health score and configuration recommendations

🏗️ Project Context Analysis

sniff context

Comprehensive project structure and context analysis:

• Analyzes project information (name, version, framework, languages)
• Maps directory structure and identifies file purposes
• Detects architectural patterns and organization quality
• Provides insights into project complexity and recommendations
• Supports multiple frameworks: Next.js, React, Vue, Angular, Svelte

🚀 Pre-deployment Pipeline

sniff deploy

Comprehensive pre-deployment validation pipeline:

• Runs all quality checks in sequence (env, types, large files, imports, bundle)
• Provides deployment readiness assessment
• Shows detailed results for each check with timing information
• Fails fast on critical issues, allows warnings for non-blocking problems

⚙️ Configuration Management

sniff config init      # Initialize default configuration file
sniff config show      # Show current configuration
sniff config validate  # Validate configuration file
sniff config get types # Show configuration for specific command

Output Formats

# JSON output for programmatic usage
sniff large --json

# Quiet mode for CI environments
sniff large --quiet

# Custom configuration
sniff --config custom.toml large

🎯 Features

✅ Fully Implemented

• Interactive Menu - Beautiful terminal UI with categorized commands
• Large Files Detection - Find and refactor "smelly code" files
• TypeScript Quality Check - Comprehensive type analysis and scoring
• Unused Imports Detection - Clean up dead imports automatically
• Bundle Analysis - Optimize build output and bundle sizes
• Performance Auditing - Lighthouse integration for performance testing
• Memory Leak Detection - Monitor Node.js memory usage patterns
• Environment Validation - Check required environment variables
• Project Context Analysis - Comprehensive project structure and insights
• Pre-deployment Pipeline - Complete validation before deployment
• Configuration System - Project-specific settings and overrides

🛠️ Configuration

Create a sniff.toml file in your project root for project-specific settings:

[large_files]
threshold = 100
excluded_dirs = [
    "node_modules",
    ".next", 
    "dist",
    ".git",
    "target",
    "build",
]
excluded_files = [
    "*.min.js",
    "*.bundle.js", 
    "package-lock.json",
    "yarn.lock",
]

[large_files.severity_levels]
warning = 100
error = 200
critical = 400

[typescript]
strict_any_check = true
allow_ts_ignore = false
require_return_types = true
min_type_coverage = 80.0

[imports]
auto_fix = false
excluded_patterns = [
    "react",
    "@types/*",
]
check_dev_dependencies = true

[bundle]
max_bundle_size_mb = 2.0
max_chunk_size_mb = 0.5
build_dirs = [
    ".next",
    "dist", 
    "build",
    "out",
]
warn_on_large_chunks = true

[performance]
lighthouse_enabled = true
min_performance_score = 75.0
min_accessibility_score = 90.0
server_urls = [
    "http://localhost:3000",
    "http://localhost:3001",
    "http://localhost:8000",
    "http://localhost:8080",
]

[memory]
check_patterns = true
check_processes = true
max_process_memory_mb = 1000.0
pattern_severity_threshold = "high"

[environment]
required_vars = [
    "NODE_ENV",
    "NEXT_PUBLIC_APP_URL",
]
check_security = true
allow_empty_values = false
env_files = [
    ".env",
    ".env.local",
    ".env.development", 
    ".env.production",
]

Use sniff config init to generate a default configuration file, or sniff config show to see your current settings.

📊 Example Output

Large Files Report

🔍 Scanning for large files...

📊 Large Files Report
====================

🚨 CRITICAL FILES
  src/components/UserDashboard.tsx (423 lines) - Component
    • Break into smaller sub-components
    • Extract custom hooks for logic
    • Move utility functions to separate files

⚠️  ERROR FILES
  src/services/api.ts (287 lines) - Service
    • Split into multiple service classes
    • Extract interfaces and types
    • Use dependency injection

📈 SUMMARY
─────────
  Files scanned: 156
  Large files found: 8
  Critical: 1
  Errors: 3
  Warnings: 4

💡 TIP: Files over 100 lines are considered 'smelly code' and should be refactored

TypeScript Quality Report

🔍 Checking TypeScript type coverage...

📊 TypeScript Quality Report
===========================

🚫 'ANY' TYPE USAGE (CRITICAL)
─────────────────────────────
  src/utils/helpers.ts:42 - Usage of 'any' type detected
    💡 Consider using a more specific type

📈 SUMMARY
─────────
  Files scanned: 89
  Total issues: 12
  'any' usage: 5
  Missing return types: 4
  TS suppressions: 3

  Type Coverage Score: 87.2%

🚫 CRITICAL: Usage of 'any' type is strictly forbidden!
   All 'any' types must be replaced with specific types.

Project Context Report

🔍 Analyzing project structure and context...

📊 Project Context Report
========================

🏗️  PROJECT OVERVIEW
─────────────────────
  Name: my-nextjs-app
  Version: 1.2.0
  Description: Modern e-commerce platform
  Framework: NextJs
  Languages: [TypeScript, JavaScript, CSS, JSON]
  Total Files: 247
  Total Lines: 12,485

📁 PROJECT STRUCTURE
──────────────────────
  Key Directories:
    • src/components (45 files, 3,241 lines)
      Purpose: Components | File types: tsx, ts, css
    • src/pages (23 files, 2,156 lines)
      Purpose: Pages | File types: tsx, ts
    • src/api (18 files, 1,489 lines)  
      Purpose: Api | File types: ts
    • src/utils (12 files, 892 lines)
      Purpose: Utils | File types: ts

🏛️  ARCHITECTURE INSIGHTS
─────────────────────────
  Organization Score: 85.2%
  Complexity Level: Moderate
  Detected Patterns:
    • LayeredArchitecture
    • ComponentComposition
    • CustomHooks

🎯 Recommended Workflows

Daily Development

sniff large && sniff imports

Pre-commit Hook

sniff types && sniff env

Performance Testing

sniff perf && sniff memory

Pre-deployment (Complete Pipeline)

sniff deploy  # Runs comprehensive validation: env, types, large files, imports, bundle

Individual Checks

sniff menu           # Interactive command selection
sniff large          # Check file sizes
sniff types          # TypeScript quality
sniff imports        # Unused imports
sniff bundle         # Bundle analysis
sniff perf           # Performance audit
sniff memory         # Memory leak detection
sniff env            # Environment validation
sniff context        # Project structure analysis

🚦 Exit Codes

• 0: All checks passed
• 1: Issues found that need attention
• 2: Configuration error
• 3: Build/project setup error

🔄 CI/CD Integration

GitHub Actions

Add this workflow to .github/workflows/sniff-check.yml:

name: Code Quality Check

on:
  pull_request:
    branches: [ main, develop ]
  push:
    branches: [ main, develop ]

jobs:
  quality-check:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v4
    
    - name: Setup Node.js
      uses: actions/setup-node@v4
      with:
        node-version: '18'
        cache: 'npm'
    
    - name: Install dependencies
      run: npm ci
    
    - name: Install sniff-check
      run: npx sniff-check@latest --version || npm install -g sniff-check
    
    - name: Run code quality checks
      run: |
        echo "🔍 Running sniff-check quality analysis..."
        sniff large --json > large-files.json
        sniff types --json > type-issues.json
        sniff imports --json > unused-imports.json
        
        # Show results in human-readable format
        echo "📊 Large Files Report:"
        sniff large
        
        echo "📝 TypeScript Quality:"
        sniff types
        
        echo "🚫 Unused Imports:"
        sniff imports
        
        echo "🏗️ Project Context:"
        sniff context
    
    - name: Upload reports as artifacts
      uses: actions/upload-artifact@v4
      if: always()
      with:
        name: sniff-check-reports
        path: |
          large-files.json
          type-issues.json
          unused-imports.json
        retention-days: 30
    
    - name: Comment PR with results
      if: github.event_name == 'pull_request'
      uses: actions/github-script@v7
      with:
        script: |
          const fs = require('fs');
          try {
            const largeFiles = JSON.parse(fs.readFileSync('large-files.json', 'utf8'));
            const typeIssues = JSON.parse(fs.readFileSync('type-issues.json', 'utf8'));
            
            let comment = '## 🔍 Code Quality Report\n\n';
            comment += `**Large Files:** ${largeFiles.summary.large_files_found} found\n`;
            comment += `**Type Issues:** ${typeIssues.summary.total_issues} found\n`;
            comment += `**Type Coverage:** ${typeIssues.summary.type_coverage_score.toFixed(1)}%\n\n`;
            
            if (largeFiles.summary.critical > 0) {
              comment += '🚨 **Critical:** Files over 400 lines found - immediate refactoring needed!\n';
            }
            
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: comment
            });
          } catch (error) {
            console.log('Could not create PR comment:', error);
          }

  performance-check:
    runs-on: ubuntu-latest
    if: github.event_name == 'pull_request'
    
    steps:
    - uses: actions/checkout@v4
    
    - name: Setup Node.js
      uses: actions/setup-node@v4
      with:
        node-version: '18'
        cache: 'npm'
    
    - name: Install dependencies
      run: npm ci
    
    - name: Build project
      run: npm run build
    
    - name: Install sniff-check
      run: npm install -g sniff-check
    
    - name: Run performance analysis
      run: |
        sniff bundle --json > bundle-analysis.json
        sniff perf --json > performance-audit.json || echo "Performance audit skipped (no dev server)"
        sniff memory --json > memory-check.json
        
        # Show bundle analysis
        echo "📦 Bundle Analysis:"
        sniff bundle
    
    - name: Upload performance reports
      uses: actions/upload-artifact@v4
      with:
        name: performance-reports
        path: |
          bundle-analysis.json
          performance-audit.json
          memory-check.json

Pre-deployment Pipeline

For production deployments:

name: Pre-deployment Check

on:
  push:
    branches: [ main ]

jobs:
  deploy-check:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v4
    
    - name: Setup Node.js
      uses: actions/setup-node@v4
      with:
        node-version: '18'
        cache: 'npm'
    
    - name: Install dependencies
      run: npm ci
    
    - name: Install sniff-check
      run: npm install -g sniff-check
    
    - name: Run complete deployment validation
      run: |
        echo "🚀 Running complete pre-deployment validation..."
        sniff deploy
        
        # Additional context analysis
        echo "📊 Final project analysis:"
        sniff context --json > final-context.json
    
    - name: Block deployment on critical issues
      run: |
        # This will fail the workflow if critical issues are found
        if sniff types --quiet | grep -q "CRITICAL"; then
          echo "❌ Critical type issues found - blocking deployment"
          exit 1
        fi
        
        if sniff large --quiet | grep -q "CRITICAL"; then
          echo "❌ Critical large files found - blocking deployment"
          exit 1
        fi
        
        echo "✅ All checks passed - ready for deployment"

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Run cargo test and cargo fmt
5. Submit a pull request

📄 License

MIT License - see LICENSE file for details.

🙏 Acknowledgments

Built with:

• clap - Command line argument parsing
• tokio - Async runtime
• rayon - Parallel processing
• regex - Pattern matching
• colored - Terminal colors

sniff-check: The definitive code quality tool for TypeScript/Next.js projects that developers actually want to use. 🎯