What are promises in JavaScript?

Short answer: Promises handle asynchronous operations. They represent a value that may be available now, later, or never.

Example code

let promise = new Promise((resolve, reject) => { resolve("Success!"); }); promise.then(res => console.log(res));

Real-world example (ShopNest)

The checkout button uses async/await to call /api/orders, shows a spinner, and catches network errors with a toast.

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.