React Server Components

• Add extra loop protection to React Server Functions (@ sebmarkbage #35351)

React Server Components

• Move react-server-dom-webpack/*.unbundled to private react-server-dom-unbundled (@ eps1lon #35290)
• Patch Promise cycles and toString on Server Functions (@ sebmarkbage, @ unstubbable #35289, #35345)

React Server Components

• Bring React Server Component fixes to Server Actions (@ sebmarkbage #35277)

Below is a list of all new features, APIs, and bug fixes.

Read the React 19.2 release post for more information.

New React Features

• <Activity>: A new API to hide and restore the UI and internal state of its children.
• useEffectEvent is a React Hook that lets you extract non-reactive logic into an Effect Event.
• cacheSignal (for RSCs) lets your know when the cache() lifetime is over.
• React Performance tracks appear on the Performance panel’s timeline in your browser developer tools

New React DOM Features

• Added resume APIs for partial pre-rendering with Web Streams:
  • resume: to resume a prerender to a stream.
  • resumeAndPrerender: to resume a prerender to HTML.
• Added resume APIs for partial pre-rendering with Node Streams:
  • resumeToPipeableStream: to resume a prerender to a stream.
  • resumeAndPrerenderToNodeStream: to resume a prerender to HTML.
• Updated prerender APIs to return a postponed state that can be passed to the resume APIs.

Notable changes

• React DOM now batches suspense boundary reveals, matching the behavior of client side rendering. This change is especially noticeable when animating the reveal of Suspense boundaries e.g. with the upcoming <ViewTransition> Component. React will batch as much reveals as possible before the first paint while trying to hit popular first-contentful paint metrics.
• Add Node Web Streams (prerender, renderToReadableStream) to server-side-rendering APIs for Node.js
• Use underscore instead of : IDs generated by useId

All Changes

React

• <Activity /> was developed over many years, starting before ClassComponent.setState (@ acdlite @ sebmarkbage and many others)
• Stringify context as "SomeContext" instead of "SomeContext.Provider" (@ kassens #33507)
• Include stack of cause of React instrumentation errors with %o placeholder (@ eps1lon #34198)
• Fix infinite useDeferredValue loop in popstate event (@ acdlite #32821)
• Fix a bug when an initial value was passed to useDeferredValue (@ acdlite #34376)
• Fix a crash when submitting forms with Client Actions (@ sebmarkbage #33055)
• Hide/unhide the content of dehydrated suspense boundaries if they resuspend (@ sebmarkbage #32900)
• Avoid stack overflow on wide trees during Hot Reload (@ sophiebits #34145)
• Improve Owner and Component stacks in various places (@ sebmarkbage, @ eps1lon: #33629, #33724, #32735, #33723)
• Add cacheSignal (@ sebmarkbage #33557)

React DOM

• Block on Suspensey Fonts during reveal of server-side-rendered content (@ sebmarkbage #33342)
• Use underscore instead of : for IDs generated by useId (@ sebmarkbage, @ eps1lon: #32001, #33342#33099, #33422)
• Stop warning when ARIA 1.3 attributes are used (@ Abdul-Omira #34264)
• Allow nonce to be used on hoistable styles (@ Andarist #32461)
• Warn for using a React owned node as a Container if it also has text content (@ sebmarkbage #32774)
• s/HTML/text for for error messages if text hydration mismatches (@ rickhanlonii #32763)
• Fix a bug with React.use inside React.lazy-ed Component (@ hi-ogawa #33941)
• Enable the progressiveChunkSize option for server-side-rendering APIs (@ sebmarkbage #33027)
• Fix a bug with deeply nested Suspense inside Suspense fallback when server-side-rendering (@ gnoff #33467)
• Avoid hanging when suspending after aborting while rendering (@ gnoff #34192)
• Add Node Web Streams to server-side-rendering APIs for Node.js (@ sebmarkbage #33475)

React Server Components

• Preload <img> and <link> using hints before they're rendered (@ sebmarkbage #34604)
• Log error if production elements are rendered during development (@ eps1lon #34189)
• Fix a bug when returning a Temporary reference (e.g. a Client Reference) from Server Functions (@ sebmarkbage #34084, @ denk0403 #33761)
• Pass line/column to filterStackFrame (@ eps1lon #33707)
• Support Async Modules in Turbopack Server References (@ lubieowoce #34531)
• Add support for .mjs file extension in Webpack (@ jennyscript #33028)
• Fix a wrong missing key warning (@ unstubbable #34350)
• Make console log resolve in predictable order (@ sebmarkbage #33665)

React Reconciler

• createContainer and createHydrationContainer had their parameter order adjusted after on* handlers to account for upcoming experimental APIs

eslint-plugin-react-hooks@6.1.0

Note: Version 6.0.0 was mistakenly released and immediately deprecated and untagged on npm. This is the first official 6.x major release and includes breaking changes.

• Breaking: Require Node.js 18 or newer. (@ michaelfaith in #32458)
• Breaking: Flat config is now the default recommended preset. Legacy config moved to recommended-legacy. (@ michaelfaith in #32457)
• New Violations: Disallow calling use within try/catch blocks. (@ poteto in #34040)
• New Violations: Disallow calling useEffectEvent functions in arbitrary closures. (@ jbrown215 in #33544)
• Handle React.useEffect in addition to useEffect in rules-of-hooks. (@ Ayc0 in #34076)
• Added react-hooks settings config option that to accept additionalEffectHooks that are used across exhaustive-deps and rules-of-hooks rules. (@ jbrown215) in #34497

React Server Components

• Move react-server-dom-webpack/*.unbundled to private react-server-dom-unbundled (@ eps1lon #35290)
• Patch Promise cycles and toString on Server Functions (@ sebmarkbage, @ unstubbable #35289, #35345)

React Server Components

• Bring React Server Component fixes to Server Actions (@ sebmarkbage #35277)

React

• Fixed Owner Stacks to work with ES2015 function.name semantics (#33680 by @ hoxyq)