Every React codebase, every Node project, every interview assumes these. Quick tour with the exact syntax.
The list
// 1. Destructuring
const { name, cgpa = 0 } = student;
const [first, ...rest] = list;
// 2. Spread
const merged = { ...defaults, ...options };
const copy = [...arr];
// 3. Template literals
const msg = `Hi ${name}, CGPA ${cgpa}`;
// 4. Arrow functions
const double = n => n * 2;
// 5. Default params
function greet(name = "friend") {}
// 6. Optional chaining + nullish coalescing
const city = user?.address?.city ?? "Chennai";
// 7. Modules
import { helper } from "./utils.js";
// 8. Map & Set
const unique = [...new Set([1,1,2])]; // [1,2]
// 9. for...of
for (const item of items) {}
// 10. Shorthand properties
const point = { x, y }; // instead of {x: x, y: y}Each has a full lesson in our JavaScript course, and they appear throughout the interview question bank.