Code Style

Core Philosophy

Code should be self-explanatory. Comments explain WHY, not WHAT.

Function Design

Small and Focused

Each function should do one thing well. Split larger functions into smaller, independent methods.

Either Call Or Pass

A function should either:

• Call other methods (high-level orchestration), OR

• Pass data / perform low-level operations

Never mix abstraction levels in one function body. This is the Single Level of Abstraction (SLA) principle.

// BAD - mixed abstraction levels function processOrder(order: Order) { validateOrder(order); // high-level call const tax = order.total * 0.1; // low-level calculation await sendConfirmation(order); // high-level call db.insert('orders', { ...order, tax }); // low-level operation }

// GOOD - consistent abstraction function processOrder(order: Order) { validateOrder(order); const enrichedOrder = calculateTaxes(order); await persistOrder(enrichedOrder); await sendConfirmation(enrichedOrder); }

Never Use If With Else

Prefer guard clauses or polymorphism over if-else blocks.

// BAD function getDiscount(user: User) { if (user.isPremium) { return 0.2; } else { return 0; } }

// GOOD - guard clause function getDiscount(user: User) { if (!user.isPremium) return 0; return 0.2; }

Avoid Flag Arguments

Flag arguments indicate a function is doing more than one thing.

// BAD function createUser(data: UserData, sendEmail: boolean) { ... }

// GOOD function createUser(data: UserData) { ... } function createUserAndNotify(data: UserData) { ... }

Naming

Expressive Over Comments

// BAD const d = 7; // days in recovery period

// GOOD const daysInRecoveryPeriod = 7;

No Abbreviations

// BAD getUserCmt(), calcRecReq()

// GOOD getUserComment(), calculateRecoveryRequirement()

Booleans Read Like Questions

// BAD eligible, recovery

// GOOD isEligible, isRecovering, hasPassedDeadline

Collections Use Plurals

// BAD const post = getPosts();

// GOOD const posts = getPosts();

Use Intermediate Variables

const hasRequiredPostCount = posts.length >= 2; const isWithinRecoveryWindow = new Date() <= recoveryDeadline; const canStartRecovery = hasRequiredPostCount && isWithinRecoveryWindow;

Constants

No Magic Numbers

// BAD if (streak >= 21) { ... }

// GOOD const GOLD_BADGE_STREAK_THRESHOLD = 21; if (streak >= GOLD_BADGE_STREAK_THRESHOLD) { ... }

Comments

Sparingly and Meaningful

• Code tells HOW, comments tell WHY

• If you need a comment, first try better naming

• Use TODO: for known limitations

• Delete obsolete comments