React Files

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, [https://github.com/facebook/react/pull/33342](https://github.com/facebook/react/pull/33342)[#33099](https://github.com/https://github.com/facebook/react/pull/33342/issues/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