boy-scout-rule（童子军规则）

Boy Scout Rule

"Leave the campground cleaner than you found it."

Always leave code better than you found it. Make incremental improvements when you touch a file.

What to Improve

Code Quality:

• Remove dead code (commented blocks, unused functions)
• Fix linting issues in files you touch
• Improve unclear naming (x, temp, data → descriptive)
• Add type annotations (TypeScript/Elixir @spec)
• Extract magic numbers to named constants
• Simplify complex logic
• Add missing error handling
• Update outdated comments
• Fix formatting
• Remove unused imports/variables
• Consolidate duplication

What NOT to Do

• ❌ Massive unrelated refactors
• ❌ Change behavior without tests
• ❌ Fix everything in the file (stay focused)
• ❌ Breaking changes without tests
• ❌ Premature optimization
• ❌ Change unrelated sections

Process

1. Before changes: Read file, note obvious issues, run linter
2. Make primary changes: Implement feature/fix, write tests
3. Apply improvements: Fix linting, improve naming, add types, extract constants, remove dead code
4. Run verification: mix lint && mix test or yarn test:lint && yarn ts:check && yarn test
5. Document: Include boy scout changes in commit message

Example Commit Message

Add worker search filter

- Implement location-based filtering
- Add tests for search radius

Boy Scout improvements:
- Extract SEARCH_RADIUS constant
- Add type annotations to helper functions
- Remove unused import statements
- Improve variable naming in search logic

Example Improvements

Before:

function calculateTotal(items) {  // No types
  let t = 0;  // Poor naming
  for (let i = 0; i < items.length; i++) {  // Old-style
    t += items[i].price * 1.08;  // Magic number
  }
  return t;
}

After:

const TAX_RATE = 1.08;

function calculateTotal(items: Item[]): number {
  return items.reduce((total, item) => {
    return total + (item.price * TAX_RATE);
  }, 0);
}

Improvements: types, constant, naming, modern syntax, simplified.

Critical Rules

• Keep improvements in same commit as primary changes
• Focus on "blast radius" (code near your changes)
• Prioritize readability over cleverness
• Always run full test suite after improvements
• Ask for help when unsure about business logic
• Small improvements > perfect refactors

Checklist

• Removed dead code in files I touched
• Fixed linting issues
• Improved naming where I made changes
• Added type annotations where missing
• Extracted magic numbers
• Updated outdated comments
• Removed unused imports
• Simplified complex logic
• Added error handling
• All tests pass
• No new linting errors
• Documented in commit message

Integration

During implementation: Make changes, apply boy scout, verify, commit together

During code review: Look for boy scout opportunities, recognize good boy scouting

During bug fixes: Fix bug, improve surrounding code, add tests, clean up

Remember

Incremental improvement, not perfection

• Small improvements compound over time
• Every file touched is an opportunity
• Be a good steward of the codebase
• When in doubt, ask for review on larger improvements