19.3.0

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

Read the React 19.3 release post for more information.

New React Features

• <ViewTransition />: Adds <ViewTransition /> and addTransitionType APIs to power View Transition animations in React (@sebmarkbage, @jackpope, @gaearon: #31975, #31987, #31996, #31999, #32001, #32002, #32028, #32029, #32031, #32034, #32038, #32041, #32050, #32090, #32105, #32254, #32379, #32422, #32462, #32540, #32545, #32585, #32599, #32611, #32612, #32617, #32651, #32653, #32656, #32664, #32699, #32723, #32734, #32751, #32752, #32760, #32761, #32764, #32772, #32790, #32819, #32820, #32822, #32833, #32849, #33094, #33191, #33200, #33206, #33293, #33330, #33331, #33332, #33357, #33362, #33433, #33576, #34374, #34450, #34481, #34500, #34502, #34510, #34511, #34539, #35567, #35564, #35485, #35380, #35063, #35060, #34676, #36917, #35337, #35520)
• Fragment Refs: Add Refs to <Fragment /> to support composable platform behavior (@jackpope, @sebmarkbage, @eps1lon, @Dhakshin2007, @chirokas, @teamleaderleo, @fallintoplace: #32465, #32613, #32619, #32654, #32660, #32682, #32722, #32813, #32814, #33056, #33058, #33093, #34069, #34103, #34544, #34545, #37062, #37061, #37060, #36047, #36010, #35642, #35641, #35637, #35630, #34935, #37457, #37408, #37326, #37251, #37171, #37169, #37168, #37167, #37166, #37165, #37164, #37163, #37162, #37161, #37160, #37125, #37063)

New React DOM Features

• browser(): a new react-dom API that returns a usable which errors during server rendering and resolves in the browser. use(browser()) inside a <Suspense> boundary marks a subtree as browser-only without reporting a recoverable error (@gnoff: #37143, #37241)
  • Added an onBrowserBailout option to the react-dom/server APIs to observe when a subtree defers to the browser (@gnoff #37193)

Notable changes

• Enable Trusted Types API integration (@rickhanlonii #35816)
• Transitions now render independently instead of being entangled into a single render, so a slow transition no longer holds up unrelated ones (@acdlite #37290)
• Added a DEV-only warning when a component appears to have been unblocked by calling use() conditionally (@hoxyq, @eps1lon: #37104, #37203, #37491)

All Changes

React

• Fast Refresh Fixes
  • Fix Fast Refresh to find and remount edits to components wrapped behind lazy() (@sophiebits #36965)
  • Fix Fast Refresh so edits to a memo() comparison function take effect (@sophiebits #36964)
  • Fix Fast Refresh crash when an edit changes the kind of a component's type (@sophiebits #36963)
  • Unify hot reload type resolution for Fast Refresh (@sophiebits #36962)
  • Fix Fast Refresh to remount correctly when an edit changes the component kind (@sophiebits #36950)
  • Double invoke effects in StrictMode after Fast Refresh (@eps1lon #35962)
• Performance Track Fixes
  • Prevent crash when accessing $$typeof in Performance Tracks (@eps1lon #35679)
  • Handle non-string function names in Performance Tracks (@eps1lon #35659)
  • Use minus (-) instead of en dash for removed props in Performance Tracks (@eps1lon #35649)
  • Handle arrays with bigints in deep objects in Performance Tracks (@eps1lon #35648)
  • Don't enumerate typed array props in Performance Tracks in DEV (@UditDewan #36913)
  • Bail out of diffing wide objects and arrays in Performance Tracks (@eps1lon #34742)
  • Clear potentially large performance measures in DEV (@hoxyq #34803)
  • Fix missing else branch for renders with no props change in Performance Tracks (@hoxyq #34837)
• Activity Fixes
  • Fix useSyncExternalStore missing store mutations that happened while an Activity tree was hidden (@sophiebits #36947)
  • Hide portal contents when an Activity is hidden (@acdlite #35091)
  • Prevent metadata hoisting in hidden <Activity> trees (@ronnakamoto #34983)
  • Prevent errors thrown inside a hidden Activity from escaping to the visible UI (@acdlite #35074)
  • Don't unhide a node if a direct parent Offscreen is still hidden (@sebmarkbage #34821)
  • Don't show internal <Offscreen> component in error messages (@rickhanlonii #35763)
• Warn in DEV when a component appears to have been unblocked by a conditional use() (@hoxyq, @eps1lon: #37104, #37203, #37491)
• Render transitions independently instead of entangling them into a single render (@acdlite #37290)
• Fix hang when updating a dehydrated boundary inside a hidden tree (@gaearon #37135)
• Don't reacquire Host Singletons during dev effect validation (@gnoff #37113)
• Only remove properties from Host Singletons on release (@gnoff #37112)
• Don't invoke effects on moved children in StrictMode (@sophiebits #36948)
• Throw a clearer error when a rejected Promise is incorrectly instrumented (@eps1lon #36328)
• Fix context propagation into Suspense fallbacks (@acdlite #36160)
• Fix context propagation through suspended Suspense boundaries (@acdlite #35839)
• Fix useDeferredValue getting stuck (@gaearon #36134)
• Update useActionState error message to say "action state" instead of "form state" (@rickhanlonii #35790)
• Don't warn when rendering data block scripts (@eps1lon #35953)
• Treat fibers with alternates as mounted in getNearestMountedFiber (@sebmarkbage #35578)
• Always instrument the lazy initializer thenable (@gnoff #35521)
• Annotate cascading updates for DevTools performance tracks in DEV (@huntie #34961)
• Resolve the .default export of a React.lazy as the canonical value (@sebmarkbage #34906)
• Limit owner stacks to 10 frames (@eps1lon #34864)
• Ensure useEffectEvent reads latest values in forwardRef and memo() components (@eps1lon #34831)

React DOM

• Copy source onto the synthetic toggle event (@lazerg #37389)
• Update HTML parser rules for the new <select> parser (@josepharhar #34804)
• Update defaultValue for type="number" inputs to match other input types (@sophiebits #36980)
• Avoid setting innerHTML when it hasn't changed (@sophiebits #36949)
• Forward the nonce option in ReactDOM.preloadModule() (@UditDewan #36851)
• Support fetchPriority for module resources (@TheAlexLichter #36835)
• Track stylesheet preloads when explicitly preloaded to avoid unnecessary suspension (@gnoff #36386)
• Suggest correct casing for the misspelled credentialless iframe attribute (@vmx906 #36322)
• Add credentialless as a recognized boolean attribute for iframes (@vmx906 #36148)
• Prevent reentrant finishedTask from calling completeAll multiple times (@gnoff #36287)
• Update the CSS shorthand property list (@kidonng #35636)
• Support the maskType SVG prop (@sleitor #35921)
• Add support for onFullscreenChange and onFullscreenError events (@chirokas #34621)
• Include submitter in submit events (@eps1lon #35590)
• Fire onReset when automatically resetting forms (@eps1lon #35176)
• Use the FormData submitter parameter (@jenseng #29028)
• Fix form status reset when component state is updated (@eps1lon #34075)
• Batch updates from resize events until the next frame (@eps1lon #35117)

React Server

• Add nonce to rendered import maps (@mattcosta7 #37339)
• Add an onBrowserBailout option to observe subtrees that defer to the browser (@gnoff #37193)
• Stop the caller's signal from retaining a finished render (@unstubbable #37315)
• Construct the render lifetime controller only when it is needed (@unstubbable #37357)
• Fix react-dom/server hanging on Deno (@fraidev #35235)
• Extend stack overflow recovery to retries in SSR (@jackpope #36977)
• Fix false-positive hydration mismatch on nonce attributes (@MaxwellCohen #37030)
• Guard shell-error callbacks instead of nulling them out on the request (@eps1lon #36916)
• Stop firing onAllReady after the shell errored (@eps1lon #36903)
• Treat an incomplete tree as an error during error recovery (@acdlite #36911)
• Fix non-script modulepreload tracking (@fallintoplace #36564)
• Finalize postponed nextSegmentId after the prelude flush (@gaojude #36779)
• Preserve referrerPolicy in image preload headers (@ulises-jeremias #36803)
• Allow pending work to specialize abort reasons (@gnoff #36586)
• Abort tasks that suspend after aborting during render (@gnoff #36585)
• Finish abort in a scheduled task (@gnoff #36580)
• Fix aborts during resumed rendering (@gnoff #36584)
• Track abort state on the request (@gnoff #36583)
• Model external work scheduling explicitly in the fb bundle (@gnoff #36576)
• Continue reporting aborted task errors after a fatal abort (@gnoff #36575)
• Disallow abort reentrancy (@gnoff #36574)
• Stop transpiling computed property names (@eps1lon #36542)
• Fix crash when capturing the callsite of a stalled use() of a rejected Flight chunk (@lubieowoce #36544)
• Double invoke effects in Strict Mode during hydration (@eps1lon #35961)
• Add additional task reentrancy protections in Fizz (@gnoff #36291)
• Don't outline Suspense boundaries with suspensey CSS during shell flush (@gnoff #35824)
• Push a stalled use() to the owner stack and debug task (@eps1lon #35226)
• Fix useId tracking on replay (@gnoff #35518)
• Correctly handle replaying when hydrating (@gnoff #35494)
• Simplify the createSuspenseBoundary path (@sebmarkbage #35087)
• Unify preamble-only fields to save a field on Suspense boundaries (@sebmarkbage #35068)
• Unify prerender-only fields to save a field on Suspense boundaries (@sebmarkbage #35067)
• Push halted awaits to the owner stack for late-arriving I/O info (@unstubbable #35019)
• Include all Node.js APIs in the Bun entrypoint for react-dom/server (@RiskyMH #34193)
• Detach a Suspense boundary after flushing its segment (@gnoff #34694)

React Server Components

• Keep an element pending while a referenced row is resolving (@unstubbable #37542)
• Fix RangeError from exponential debug info growth (@unstubbable #37481)
• Abort the cache signal when debug objects are retained (@unstubbable #37342)
• Transfer key validation of lazy nodes when they are unwrapped (@unstubbable #37258)
• Add pending_weak to the Flight thenable protocol (@acdlite #37154)
• Outline and dedupe repeated strings (@gaearon #37147)
• Port Reply Server traversal guards to the Flight Client (@eps1lon #37144)
• Define Flight chunk .then with Object.defineProperty (@eps1lon #37109)
• Support Turbopack's experimental array format for chunks (@sampoder #37095)
• Limit fake JSX call site stacks to 10 frames (@timneutkens #37086)
• Improve performance when decoding Flight replies (@gnoff #37090)
• Recognize Node 22+ V8 frames for Promise statics in debug info (@gaearon #36969)
• Tailor the warning for binary data serialized through toJSON (Node Buffer) (@unstubbable #36873)
• Resolve models before JSON.stringify for faster serialization (@mhart #36795)
• Prune debug info when chunks error (@gnoff #36782)
• Avoid main-thread stalls from large debug strings (@unstubbable #36570)
• Fix stranded row content under Node stream backpressure (@unstubbable #36516)
• Fix dropped FormData entries in decodeReplyFromBusboy (@unstubbable #36468)
• Harden types and improve performance of Flight replies (@eps1lon #36425)
• Add more cycle protections to Flight replies (@eps1lon #36236)
• Transport AggregateError.errors (@eps1lon #36156)
• Bail out early when a backing entry for Blob deserialization is not a Blob (@eps1lon #36055)
• Clear chunk reason after successful module initialization (@unstubbable #36024)
• Add support for transporting Error.cause (@eps1lon #35810)
• Walk parsed JSON instead of using a reviver for faster RSC payload parsing (@timneutkens #35776)
• Skip transferReferencedDebugInfo during debug info resolution (@unstubbable #35795)
• Add unstable_allowPartialStream option to Flight Client (@unstubbable #35731)
• Fix encodeReply for JSX with temporary references (@unstubbable #35730)
• Fix debug channel flag in Node.js renderToPipeableStream (@feedthejim #35724)
• Fix stack overflow in visitAsyncNode with deep async chains (@unstubbable #35612)
• Allow Server Components to render context providers from client modules (@rickhanlonii #35675)
• Allow overriding request.timeOrigin via options.startTime (@lubieowoce #35598)
• Warn once if eval is disabled in the dev environment (@eps1lon #35661)
• Restore original function name in dev server callstacks served with unsafe-eval (@eps1lon #35650)
• Fix react-markup types for server references (@eps1lon #35634)
• Add more DoS mitigations to Flight replies and harden Flight (@unstubbable #35632)
• Allow cyclic references to be serialized when unwrapping lazy elements (@unstubbable #35471)
• Improve cyclic thenable detection in Flight reply server (@cvan20191 #35369)
• Add extra loop protection to Flight reply server (@sebmarkbage #35351)
• Patch Promise cycles and toString on Server Functions (@sebmarkbage #35345)
• Move react-server-dom-webpack/*.unbundled to private react-server-dom-unbundled (@eps1lon #35290)
• Never parse then functions in Flight replies (@sebmarkbage #35289)
• Patch Flight reply server with fixes from Flight Client (@sebmarkbage #35277)
• Complete the list of Node.js internal Promise awaits (@eps1lon #35161)
• Reduce risk of maximum call stack exceeded when emitting async sequences (@eps1lon #35159)
• Fix pending chunks count for streams and async iterables in DEV (@unstubbable #35143)
• Fix broken byte stream parsing caused by buffer detachment (@unstubbable #35127)
• Fix hasReadable flag in Node.js clients' debug channel (@unstubbable #35039)
• Fix debug info filtering to include later resolved I/O (@unstubbable #35036)
• Cache the value when visiting the same I/O or Promise along different paths (@sebmarkbage #35005)
• Clone subsequent I/O nodes when resolved more than once (@sebmarkbage #35003)
• Fix hang after resolving cyclic references (@unstubbable #34988)
• Allow passing DEV-only startTime as an option (@sebmarkbage #34912)
• Ignore bound-anonymous-fn resources as they're not considered I/O (@sebmarkbage #34911)
• Fix detached ArrayBuffer error when streaming typed arrays (@unstubbable #34849)
• Exclude RSC stream if the stream resolves in a task (@sebmarkbage #34838)
• Forward the current environment when forwarding I/O entries (@sebmarkbage #34836)
• Look for moved debug info when logging component performance track (@sebmarkbage #34839)
• Respect displayName of Promise instances on the server (@sebmarkbage #34825)
• Avoid unnecessary indirection when serializing debug info (@unstubbable #34797)
• Fix preload as attribute for stylesheets (@unstubbable #34760)
• Don't serialize toJSON in debug path and omit wide arrays (@sebmarkbage #34759)
• Add support for <Activity> (@eps1lon #34697)