coding-standards

Coding Standards & Best Practices

Universal coding standards applicable across all projects.

When to Activate

• Starting a new project or module
• Reviewing code for quality and maintainability
• Refactoring existing code to follow conventions
• Enforcing naming, formatting, or structural consistency
• Setting up linting, formatting, or type-checking rules
• Onboarding new contributors to coding conventions

Code Quality Principles

1. Readability First

• Code is read more than written
• Clear variable and function names
• Self-documenting code preferred over comments
• Consistent formatting

2. KISS (Keep It Simple)

• Simplest solution that works
• Avoid over-engineering
• No premature optimization
• Easy to understand > clever code

3. DRY (Don't Repeat Yourself)

• Extract common logic into functions
• Create reusable components
• Share utilities across modules

4. YAGNI (You Aren't Gonna Need It)

• Don't build features before they're needed
• Avoid speculative generality
• Start simple, refactor when needed

TypeScript/JavaScript Standards

Variable Naming

// GOOD: Descriptive names
const searchQuery = 'election'
const isUserAuthenticated = true
const totalRevenue = 1000

// BAD: Unclear names
const q = 'election'
const flag = true
const x = 1000

Function Naming

// GOOD: Verb-noun pattern
async function fetchItemData(itemId: string) { }
function calculateSimilarity(a: number[], b: number[]) { }
function isValidEmail(email: string): boolean { }

// BAD: Unclear or noun-only
async function item(id: string) { }
function similarity(a, b) { }

Immutability Pattern (CRITICAL)

// ALWAYS use spread operator
const updatedUser = { ...user, name: 'New Name' }
const updatedArray = [...items, newItem]

// NEVER mutate directly
user.name = 'New Name'  // BAD
items.push(newItem)     // BAD

Error Handling

// GOOD: Comprehensive error handling
async function fetchData(url: string) {
  try {
    const response = await fetch(url)

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`)
    }

    return await response.json()
  } catch (error) {
    console.error('Fetch failed:', error)
    throw new Error('Failed to fetch data')
  }
}

Async/Await Best Practices

// GOOD: Parallel execution when possible
const [users, items, stats] = await Promise.all([
  fetchUsers(),
  fetchItems(),
  fetchStats()
])

// BAD: Sequential when unnecessary
const users = await fetchUsers()
const items = await fetchItems()
const stats = await fetchStats()

Type Safety

// GOOD: Proper types
interface Item {
  id: string
  name: string
  status: 'active' | 'resolved' | 'closed'
  created_at: Date
}

function getItem(id: string): Promise<Item> {
  // Implementation
}

// BAD: Using 'any'
function getItem(id: any): Promise<any> {
  // Implementation
}

React Best Practices

Component Structure

interface ButtonProps {
  children: React.ReactNode
  onClick: () => void
  disabled?: boolean
  variant?: 'primary' | 'secondary'
}

export function Button({
  children,
  onClick,
  disabled = false,
  variant = 'primary'
}: ButtonProps) {
  return (
    <button
      onClick={onClick}
      disabled={disabled}
      className={`btn btn-${variant}`}
    >
      {children}
    </button>
  )
}

Custom Hooks

export function useDebounce<T>(value: T, delay: number): T {
  const [debouncedValue, setDebouncedValue] = useState<T>(value)

  useEffect(() => {
    const handler = setTimeout(() => {
      setDebouncedValue(value)
    }, delay)

    return () => clearTimeout(handler)
  }, [value, delay])

  return debouncedValue
}

State Management

const [count, setCount] = useState(0)

// GOOD: Functional update for state based on previous state
setCount(prev => prev + 1)

// BAD: Direct state reference (can be stale in async scenarios)
setCount(count + 1)

API Design Standards

REST API Conventions

GET    /api/items              # List all items
GET    /api/items/:id          # Get specific item
POST   /api/items              # Create new item
PUT    /api/items/:id          # Update item (full)
PATCH  /api/items/:id          # Update item (partial)
DELETE /api/items/:id          # Delete item

# Query parameters for filtering
GET /api/items?status=active&limit=10&offset=0

Response Format

interface ApiResponse<T> {
  success: boolean
  data?: T
  error?: string
  meta?: {
    total: number
    page: number
    limit: number
  }
}

Input Validation

import { z } from 'zod'

const CreateItemSchema = z.object({
  name: z.string().min(1).max(200),
  description: z.string().min(1).max(2000),
  endDate: z.string().datetime(),
  categories: z.array(z.string()).min(1)
})

Code Smell Detection

1. Long Functions

// BAD: Function > 50 lines — split into smaller functions
function processData() {
  const validated = validateData()
  const transformed = transformData(validated)
  return saveData(transformed)
}

2. Deep Nesting

// BAD: 5+ levels of nesting
// GOOD: Early returns
if (!user) return
if (!user.isAdmin) return
if (!item) return
// Do something

3. Magic Numbers

// BAD: Unexplained numbers
if (retryCount > 3) { }

// GOOD: Named constants
const MAX_RETRIES = 3
if (retryCount > MAX_RETRIES) { }

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Remember: Code quality is not negotiable. Clear, maintainable code enables rapid development and confident refactoring.