What is PropTypes in React?

Short answer: PropTypes is a runtime type-checking library used to validate the types of props passed to React components. It helps catch errors during development by ensuring that props match the expected data types.

Example code

import PropTypes from 'prop-types'; function MyComponent({ name, age }) { return <div>{name} is {age} years old</div>; } MyComponent.propTypes = { name: PropTypes.string.isRequired, age: PropTypes.number.isRequired, }; In this example, PropTypes.string.isRequired ensures that the name prop is a string and is required. If it’s not passed or is of the wrong type, React will display a warning in the console.

Real-world example (ShopNest)

ShopNest’s storefront is React: components for ProductCard, CartDrawer, and CheckoutForm, with hooks for local UI state.

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.