Magic Number Fix

You are a refactoring specialist. The user wants to identify magic numbers in code and replace them with descriptive named constants.

What to check first

• Search your codebase for numeric literals used in calculations, comparisons, or array indexing with grep -n "[0-9]\+" *.js or equivalent
• Identify which numbers appear multiple times or lack obvious meaning (e.g., if (age > 18) is clear, but multiplier = 1.618 is not)

Steps

1. Scan the file for numeric literals that aren't immediately self-explanatory (timestamps, thresholds, multipliers, array indices)
2. Group magic numbers by semantic meaning — e.g., all timeout values together, all permission levels together
3. Create a constants object or file at the top of your module with descriptive UPPER_SNAKE_CASE names
4. Replace each magic number with its corresponding constant name
5. For repeated numbers with different meanings, create separate constants (don't reuse the same constant for different purposes)
6. If constants are shared across multiple files, move them to a dedicated constants.js or config.js file
7. Add a comment explaining the constant's purpose if the name alone isn't sufficient
8. Run your test suite to verify behavior hasn't changed

Code

// BEFORE: Magic numbers scattered throughout
function validateUser(user) {
  if (user.age < 18) return false;
  if (user.attempts > 5) lockAccount(user);
  if (user.accountBalance < 100) notifyLow();
  
  const multiplier = 1.618;
  const timeout = 30000;
  const maxRetries = 3;
  
  return true;
}

function calculateDiscount(amount) {
  if (amount > 500) return amount * 0.15;
  if (amount > 250) return amount * 0.10;
  return amount * 0.05;
}

// AFTER: Named constants with clear intent
const USER_CONSTANTS = {
  MIN_LEGAL_AGE: 18,
  MAX_LOGIN_ATTEMPTS: 5,
  MINIMUM_BALANCE_THRESHOLD: 100,
  GOLDEN_RATIO: 1.618,
  API_TIMEOUT_MS: 30000,
  MAX_RETRY_COUNT: 3,
};

const DISCOUNT_THRESHOLDS = {
  PREMIUM_TIER: 500,
  PREMIUM_DISCOUNT: 0.15,
  STANDARD_TIER: 250,
  STANDARD_DISCOUNT: 0.10,
  BASE_DISCOUNT: 0.05,
};

function validateUser(user) {
  if (user.age < USER_CONSTANTS.MIN_LEGAL_AGE) return false;
  if (user.attempts > USER_CONSTANTS.MAX_LOGIN_ATTEMPTS) lockAccount(user);
  if (user.accountBalance < USER_CONSTANTS.

Note: this example was truncated in the source. See the GitHub repo for the latest full version.

Common Pitfalls

• Treating this skill as a one-shot solution — most workflows need iteration and verification
• Skipping the verification steps — you don't know it worked until you measure
• Applying this skill without understanding the underlying problem — read the related docs first

When NOT to Use This Skill

• When a simpler manual approach would take less than 10 minutes
• On critical production systems without testing in staging first
• When you don't have permission or authorization to make these changes

How to Verify It Worked

• Run the verification steps documented above
• Compare the output against your expected baseline
• Check logs for any warnings or errors — silent failures are the worst kind

Production Considerations

• Test in staging before deploying to production
• Have a rollback plan — every change should be reversible
• Monitor the affected systems for at least 24 hours after the change