Optional Chaining & Nullish Coalescing in JavaScript
From the JavaScript cheat sheet · Modern JavaScript (ES6+) · verified Jul 2026
Optional Chaining & Nullish Coalescing
Safe property access and default values
javascript
// Optional chaining
const city = user?.address?.city;
const result = obj.method?.();
const item = arr?.[index];
// Nullish coalescing
const value = input ?? 'default';
const port = process.env.PORT ?? 3000;💡 ?. stops evaluation and returns undefined if null/undefined
⚡ ?? only replaces null/undefined, not other falsy values
📌 Use ?? for numeric values that could be 0
🔥 Combine ?. and ?? for safe access with defaults