Linter

Linter Skill

Apply code linting, formatting, and style checks to improve code quality and consistency.

When to Use

Use this skill when the user wants to:

• Enforce code style and formatting
• Fix linting errors
• Configure linters
• Run static analysis
• Fix formatting issues
• Check for code style violations

Linter Tools

JavaScript/TypeScript

• ESLint: Linting and code style
• Prettier: Code formatting
• Husky: Git hooks
• lint-staged: Lint staged files

Python

• flake8: Linting
• black: Formatting
• isort: Import sorting
• pylint: Static analysis

Java

• Checkstyle: Linting
• SpotBugs: Static analysis
• PMD: Static analysis

General

• Standard: JavaScript style
• RuboCop: Ruby style
• Go fmt: Go formatting

Common Linting Rules

JavaScript/TypeScript

// ESLint rules example
rules: {
  'no-console': 'warn',
  'no-unused-vars': 'error',
  'prefer-const': 'error',
  'quotes': ['error', 'single'],
  'semi': ['error', 'always']
}

Python

# flake8 configuration
[flake8]
max-line-length = 100
ignore = E203, W503
exclude = .git, __pycache__, venv

Formatting Tools

Prettier Configuration

// .prettierrc
{
  "semi": true,
  "singleQuote": true,
  "tabWidth": 2,
  "trailingComma": "es5",
  "printWidth": 80
}

Black Configuration

# pyproject.toml
[tool.black]
line-length = 100
target-version = ['py39']

Integration with Git

Pre-commit Hooks

# Install husky for git hooks
npm install husky lint-staged --save-dev
npx husky install
npx husky add .husky/pre-commit "npx lint-staged"

lint-staged

// .lintstagedrc
{
  "*.{js,jsx,ts,tsx}": ["eslint --fix", "prettier --write"],
  "*.{json,md,css,scss}": ["prettier --write"]
}

Linting Best Practices

• Automatic: Run on save, not just CI
• Fail fast: Fail build on critical issues
• Fixable: Auto-fix what's possible
• Configurable: Custom rules for project
• Team-aligned: Consistent style across team

Deliverables

• Linter configuration files
• Formatters setup
• Pre-commit hooks
• CI integration
• Documentation

Quality Checklist

• Linters are configured
• Auto-fixes are applied
• Code style is consistent
• No style violations in CI
• Configuration matches project guidelines
• Documentation explains rules