What is the key prop in React and why is it important?

What is the key prop in React and why is it important?

The key prop in React is a special attribute used to identify elements in a list. It helps React optimize rendering by keeping track of which items have changed, been added, or removed.

Can you give me an example of how to use the key prop?

Sure! When rendering a list of items, you can use the key prop like this: <ul>{items.map(item => <li key={item.id}>{item.name}</li>)}</ul>. Here, 'item.id' is a unique identifier for each item.

What happens if I don't use the key prop?

If you don't use the key prop, React will use the index of the item as the key, which can lead to performance issues and bugs, especially when the list changes.

Are there any best practices for using the key prop?

Yes! Always use a unique and stable identifier for keys, avoid using array indices as keys, and ensure keys are consistent across renders.