Concurrent features

React 18 will be the first React release adding opt-in support for concurrent features such as:

• startTransition: lets you keep the UI responsive during an expensive state transition.
• useDeferredValue lets you defer updating the less important parts of the screen.
• Streaming SSR with selective hydration: lets your app load and become interactive faster.

You can start using these features in a small part of your tree without enabling Strict Mode for your entire app.

Note: if you’re familiar with concurrent “mode”, see: What happened to concurrent “mode”.