code-formatting

Skill: Code Formatting

When to Use This Skill

This skill activates when you need to:

• Format code to match project style guidelines
• Fix linting errors
• Set up automatic code formatting
• Understand project formatting standards

Prerequisites

Check project for existing formatting configuration:

• .prettierrc, .eslintrc (JavaScript/TypeScript)
• .black, pyproject.toml, ruff.toml (Python)
• .rustfmt.toml (Rust)
• .gofmt settings (Go)

Step-by-Step Workflow

Step 1: Detect Formatting Tools

Check {{lint_command}} or look for:

• package.json scripts: "format", "lint", "lint:fix"
• Configuration files in project root
• .pre-commit-config.yaml for pre-commit hooks
• CI/CD workflows for formatting checks

Step 2: Format Code by Tech Stack

Python

Option A: Black (Opinionated)

# Install
pip install black

# Format all Python files
black .

# Format specific file
black myfile.py

# Check without modifying
black --check .

# Preview changes
black --diff .

Add to pyproject.toml:

[tool.black]
line-length = 88
target-version = ['py310']
include = '\.pyi?$'
extend-exclude = '''
/(
  # directories
  \.eggs
  | \.git
  | \.venv
  | build
  | dist
)/
'''

Option B: Ruff (Fast, Modern)

# Install
pip install ruff

# Format code
ruff format .

# Check and fix linting
ruff check --fix .

# Check only
ruff check .

Add ruff.toml:

line-length = 88
target-version = "py310"

[lint]
select = ["E", "F", "I", "N", "W"]
ignore = ["E501"]

[format]
quote-style = "double"
indent-style = "space"

Option C: autopep8

# Install
pip install autopep8

# Format file
autopep8 --in-place --aggressive --aggressive myfile.py

# Format all files
find . -name '*.py' -exec autopep8 --in-place --aggressive --aggressive {} \;

JavaScript/TypeScript

Option A: Prettier

# Install
npm install --save-dev prettier

# Format all files
npx prettier --write .

# Format specific files
npx prettier --write "src/**/*.{js,jsx,ts,tsx,json,css,md}"

# Check formatting
npx prettier --check .