15 JavaScript Tips That Will Make You a Better Developer in 2026

These JavaScript tips have genuinely improved my code quality. No fluff — just patterns that work. 1. Optional Chaining is Your Best Friend // Old way - ugly and error-prone const city = user && user.address && user.address.city; // Modern way const city = user?.address?.city; // With methods const first = arr?.at(0); const len = str?.trim()?.length; 2. Nullish Coalescing vs OR // || uses any falsy value (0, '', false are falsy!) const count = data.count || 10; // BUG: returns 10 when count is 0 // ?? only triggers on null/undefined const count = data.count ?? 10; // CORRECT: returns 0 when count is 0 3. Object Destructuring with Defaults function createUser({ name, role = 'user', active = true, theme = 'light' } = {}) { return { name, role, active, theme }; } // The = {} default allows calling with no arguments createUser(); // Works! createUser({ name: 'Alice' }); // { name: 'Alice', role: 'user', active: true, theme: 'light' } 4. Array Methods Over Loops const users