complexity

Complexity Patterns

Domain expertise for code complexity and maintainability analysis. Use alongside devflow:review-methodology for complete complexity reviews.

Iron Law

IF YOU CAN'T UNDERSTAND IT IN 5 MINUTES, IT'S TOO COMPLEX

Every function should be explainable to a colleague in under 5 minutes. If you need a diagram to understand control flow, refactor. If you need comments to explain what (not why), the code is too clever. Simplicity is a feature, complexity is a bug.

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Complexity Categories

1. Cyclomatic Complexity

High decision path count makes code hard to test and understand.

Violation: Deep nesting (5+ levels)

if (order) {
  if (order.items) {
    for (const item of order.items) {
      if (item.quantity > 0) {
        if (item.product?.inStock) {
          // Buried logic

Solution: Early returns and extraction

function processOrder(order: Order) {
  if (!order?.items) return;
  for (const item of order.items) processItem(item);
}

function processItem(item: OrderItem) {
  if (item.quantity <= 0 || !item.product?.inStock) return;
  // Logic at top level
}

2. Readability Issues

Code that requires mental effort to parse.

Violation: Magic values

if (status === 3) {
  setTimeout(callback, 86400000);
}

Solution: Named constants

const OrderStatus = { COMPLETED: 3 } as const;
const ONE_DAY_MS = 24 * 60 * 60 * 1000;

if (status === OrderStatus.COMPLETED) {
  setTimeout(callback, ONE_DAY_MS);
}

3. Maintainability Issues

Code that's expensive to change.

Violation: Long parameter lists

function createUser(name, email, password, role, dept, manager, startDate, salary) { }

Solution: Object parameter

interface CreateUserParams {
  name: string; email: string; password: string;
  role: string; department: string; manager?: string;
  startDate: Date; salary: number;
}
function createUser(params: CreateUserParams) { }