Added useActionState to replace useFormState and added pending value (#28491).
October 5, 2023 (18.3.0-canary-546178f91-20231005)
React
Added support for async functions to be passed to startTransition.
useTransition now triggers the nearest error boundary instead of a global error.
Added useOptimistic, a new Hook for handling optimistic UI updates. It optimistically updates the UI before receiving confirmation from a server or external source.
React DOM
Added support for passing async functions to the action prop on <form>. When the function passed to action is marked with 'use server', the form is progressively enhanced.
Added useFormStatus, a new Hook for checking the submission state of a form.
Added useFormState, a new Hook for updating state upon form submission. When the function passed to useFormState is marked with 'use server', the update is progressively enhanced.