What are React controlled components and uncontrolled components?

A Controlled Component takes its current value through props and notifies changes through callbacks like onChange. A parent component "controls" it by handling the callback and managing its own state and passing the new values as props to the controlled component. This is also called "dumb component".

A Uncontrolled Component stores its own state internally, and you query the DOM using a ref to find its current value when you need it. This is a bit more like traditional HTML.

// Controlled:
<input type="text" value={value} onChange={handleChange} />

// Uncontrolled:
<input type="text" defaultValue="foo" ref={inputRef} />
// Use `inputRef.current.value` to read the current value of <input>

Earn bitcoins upto $250 (free), invest in other Cryptocurrencies when you signup with blockfi. Use the referral link: Signup now and earn!

Using BlockFi, don't just buy crypto - start earning on it. Open an interest account with up to 8.6% APY, trade currencies, or borrow money without selling your assets.

Join CoinBase! We'll both receive $10 in free Bitcoin when they buy or sell their first $100 on Coinbase! Available in India also. Use the referral Join coinbase!

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.