What is a callback function?

Short answer: A function passed as an argument to another function to be executed later. Example: function greet(name, callback) { console.log(`Hello, ${name}`); callback(); }

Example code

greet("Sandeep", () => console.log("Callback executed"));

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.