React: What is React event delegation?

Event delegation — single listener on root.

1function List({ items }) {
2  return (
3    <ul>
4      {items.map(item => (
5        <li key={item.id} onClick={() => handleClick(item)}>
6          {item.name}
7        </li>
8      ))}
9    </ul>
10  );
11}

Benefits: Fewer event listeners, better memory usage, dynamic lists work without cleanup, cross-browser consistency.

SyntheticEvent: Wraps native events, consistent API across browsers, pooling removed in React 17+.