Automatic Batching Divergence Between React 17 Development and React 18 Production

Automatic Batching Divergence

In React 17 development, state updates inside event handlers are automatically batched while updates in asynchronous callbacks remain unbatched.

React 18 production enables automatic batching for all updates inside event handlers, which can combine multiple setState calls into a single render and affect side‑effect ordering.

• Should developers explicitly disable automatic batching with ReactDOM.unstable_batchedUpdates in production code?
• Is migration to the concurrent APIs required to achieve consistent batching behavior across environments?
• What testing strategy can reliably verify identical render counts and side‑effect ordering in React 17 and React 18 builds?