cursor-code-style

Cursor Code Style

Rules extracted from Cursor Agent prompt for consistent, high-quality code.

Variable Naming

DO:

• Use descriptive names that reveal intent
• Functions should be verbs/verb-phrases: getUserById, calculateTotal, validateInput
• Variables should be nouns/noun-phrases: userCount, totalPrice, validationResult
• Use consistent naming conventions per language (camelCase for JS/TS, snake_case for Python)

DON'T:

• Never use 1-2 character variable names (EXCEPTION: loop counters i, j, k and coordinates x, y)
• Avoid abbreviations unless universally understood: genYmdStr -> generateDateString
• Don't use generic names: data, info, temp, result without context

Examples

Bad:  const d = getData()
Good: const userProfile = fetchUserProfile()

Bad:  function proc(x) { ... }
Good: function processPayment(transaction) { ... }

Bad:  let n = users.length
Good: let userCount = users.length

Control Flow

DO:

• Use guard clauses and early returns to reduce nesting
• Handle error and edge cases FIRST, then happy path
• Keep nesting to 2-3 levels maximum
• Prefer switch or object lookup over long if-else chains

DON'T:

• Create deeply nested if/else chains (>3 levels)
• Put the happy path inside nested conditions
• Use else after a return statement

Examples

// BAD: Deep nesting
function processUser(user) {
  if (user) {
    if (user.isActive) {
      if (user.hasPermission) {
        // happy path buried 3 levels deep
        return doWork(user)
      }
    }
  }
  return null
}

// GOOD: Guard clauses
function processUser(user) {
  if (!user) return null
  if (!user.isActive) return null
  if (!user.hasPermission) return null
  
  return doWork(user)  // happy path at top level
}

Comments

DO:

• Add comments for complex code explaining "why" not "how"
• Document non-obvious business rules
• Use JSDoc/docstrings for public APIs
• Comment regex patterns with what they match

DON'T:

• Add comments for trivial or obvious code
• Leave TODO comments (implement the fix instead)
• Write comments that restate the code
• Use comments to disable code (delete it or use version control)