React-18

React 18 improves the existing behavior of Suspense

React 18 delays committing everything inside the Suspense boundary (the suspended component and all its siblings) until the suspended data resolves.

React 18 adds automatic batching

React 18 adds out-of-the-box performance improvements by doing more batching by default.

React 18 introduces new root API ( ReactDOM.createRoot )

React 18 adds the new root API that comes up with the new out-of-the-box improvements.