JS Coding Convention

• camelCase for variables and functions: userName, getUser()
• PascalCase for classes & components: UserCard
• UPPER_SNAKE for constants: MAX_RETRIES
• Boolean prefix: is, has, can — isLoading
• Avoid abbreviations: btn ❌ → button ✅

ts
const items: Item[] = [];     // immutable reference
let count = 0;                 // re-assign
// var ❌

• Pure functions whenever possible — no side effects.
• Parameters ≤ 3. More than that → wrap them in an object.
• Early return instead of nested if.

js
// ❌
function f(user) {
  if (user) {
    if (user.active) {
      return doSomething(user);
    }
  }
}

// ✅
function f(user) {
  if (!user || !user.active) return;
  return doSomething(user);
}

js
// Spread instead of Object.assign
const merged = { ...a, ...b };

// Destructure when reading
const { name, age } = user;

// Trailing comma for easy-to-read diffs
const arr = [
  'a',
  'b',
  'c',
];

• Use async/await instead of long chained .then().
• Promise.all to run independent work in parallel.
• Always have a try/catch boundary, at least in one place.

Set up ESLint (extends next/core-web-vitals) + Prettier. Don’t argue about style in PRs — let the machine decide.