How do I use the key prop in React?

How do I use the key prop in React?

The key prop in React is used to identify elements in a list. It helps React optimize rendering by keeping track of elements.

Can you give me an example of how to use it?

Sure! When rendering a list of items, you can assign a unique key to each item like this:

{items.map(item => <ListItem key={item.id} item={item} />)}

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

If you don't use the key prop, React may have trouble identifying which items have changed, leading to inefficient updates and potential bugs.

Are there any best practices for choosing keys?

Yes! Always use unique and stable identifiers for keys, like IDs from your data, to avoid issues with reordering or filtering.