consistency

Consistency Patterns

Domain expertise for code consistency and unnecessary simplification detection. Use alongside devflow:review-methodology for complete consistency reviews.

Iron Law

MATCH EXISTING PATTERNS OR JUSTIFY DEVIATION

New code should look like existing code. If the codebase uses camelCase, use camelCase. If errors return Result types, return Result types. Consistency trumps personal preference. Deviation requires explicit justification and team agreement. One codebase, one style.

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Consistency Categories

1. Unnecessary Simplification

Content truncation, stripped configuration, removed error context.

// VIOLATION: Oversimplified error messages
const errorMessages = {
  INVALID_EMAIL: 'Invalid email',  // Was: detailed format guidance
  USER_NOT_FOUND: 'Not found',     // Was: helpful next steps
};

// CORRECT: Preserve helpful context
const errorMessages = {
  INVALID_EMAIL: 'Please enter a valid email address in the format [email protected]',
  USER_NOT_FOUND: 'We could not find an account with that email. Please check or create a new account.',
};

2. Pattern Violations

Naming conventions, error handling styles, import/export organization.

// EXISTING PATTERN: Result types
function existingFunction(): Result<User, Error> {
  if (!valid) return Err(new ValidationError('...'));
  return Ok(user);
}

// VIOLATION: Throws instead of Result
function newFunction(): User {
  if (!valid) throw new Error('...');  // Different pattern!
  return user;
}

// CORRECT: Match existing
function newFunction(): Result<User, Error> {
  if (!valid) return Err(new ValidationError('...'));
  return Ok(user);
}

3. Feature Regression

Removed CLI options, changed return types, removed event emissions.

// VIOLATION: Removed event emissions break listeners
class OrderService {
  async createOrder(data: OrderData) {
    const order = await this.repository.create(data);
    return order;  // Events removed - listeners won't fire!
  }
}

// CORRECT: Preserve all event emissions
class OrderService {
  async createOrder(data: OrderData) {
    const order = await this.repository.create(data);
    this.events.emit('order.created', order);
    this.events.emit('inventory.reserve', order.items);
    return order;
  }
}