What is the spread operator?

Short answer: Allows expanding arrays or objects. Example: let arr1 = [1, 2]; let arr2 = [...arr1, 3, 4]; // [1,2,3,4] let obj1 = { a: 1 }; let obj2 = { ...obj1, b: 2 }; // { a:1, b:2 }

Example code

Allows expanding arrays or objects. Example: let arr1 = [1, 2];
let arr2 = [...arr1, 3, 4]; // [1,2,3,4]
let obj1 = { a: 1 };
let obj2 = { ...obj1, b: 2 }; // { a:1, b:2 }

Real-world example (ShopNest)

ShopNest’s browser cart uses modern JavaScript: fetch APIs with async/await, modules, and clear error handling.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.