Key changes

iOS CSS Core Animation

Reanimated 4.4.0 introduces a new platform-backed CSS animation engine on iOS that runs animations
directly on Core Animation layers instead of going through the JS-driven update loop. It is hidden
behind the IOS_CSS_CORE_ANIMATION static feature flag.

• feat: Wire CSSPlatformTransition with iOS platform implementation by @MatiPl01 in #9325
• chore: Hide platform animations behind a feature flag by @MatiPl01 in #9493

Animation Backend

A new Animation Backend has been integrated behind a feature flag, which will help greatly with the flow of updating the Shadow Tree in animations.

• Integrate Animation Backend behind a flag by @bartlomiejbloniarz in #9279

New useTimestamp hook

A new useTimestamp hook exposes the current frame timestamp as a Shared Value that updates every
frame with the time elapsed since the first frame, with an isActive flag to pause and resume updates.

• Adds useTimestamp hook by @ashfurrow in #9162

Precompiled headers on Android

Reanimated's native build on Android now uses precompiled headers (ReanimatedPCH.h), significantly
reducing C++ compile times for both fresh and incremental builds.

• Start using precompiled headers on Android by @tomekzaw in #9434

Other changes

• fix(Reanimated): Spring jitter by @piaskowyk in #9463
• feat: emit ESM package json by @tjzel in #9481
• Add support for placeholderTextColor in synchronous props by @tomekzaw in #9409
• Add support for shadowColor in synchronous props by @tomekzaw in #9411
• Add support for shadowOffset in synchronous props by @tomekzaw in #9412
• Add support for outlineColor, outlineOffset and outlineWidth in synchronous props by @tomekzaw in #9417
• Add support for borderBlockColor, borderBlockStartColor and borderBlockEndColor in synchronous props by @tomekzaw in #9418
• Unify synchronous props logic between platforms by @tomekzaw in #9381
• Preallocate and reuse synchronous props buffers on Android by @tomekzaw in #9425
• fix(Reanimated): laggy LA outside of Animation Backend by @tjzel in #9431
• feat: CSSPlatformAnimation abstraction by @MatiPl01 in #9278
• feat: CSSPlatformTransition abstraction by @MatiPl01 in #9324
• chore: Rename EXPERIMENTAL_PLATFORM_CSS_ANIMATIONS to IOS_CSS_CORE_ANIMATION by @MatiPl01 in #9506
• fix(Reanimated): RCTModernEventEmmitter for older RN by @tjzel in #9181
• chore(Reanimated): post release 4.3.0 by @tjzel in #9182
• Add check for conflicting feature flags by @tomekzaw in #9174
• Store ShadowNodeFamily instead of ShadowNode in UpdatesRegistry by @tomekzaw in #9156
• Store ShadowNodeFamily::Shared instead of ShadowNodeFamily * in PropsMap and ChildrenMap by @tomekzaw in #9184
• Remove useInterpolateConfig function and InterpolateConfig and ColorSpace types by @tomekzaw in #9150
• Bump React Native to 0.85.0-rc.6 by @tomekzaw in #9193
• Update doNotStrip to keepDebugSymbols by @wisniewskij in #8636
• Migrated packages/react-native-reanimated java->kotlin by @tshmieldev in #9163
• removed JSCallInvokerResolver.kt by @tshmieldev in #9198
• chore: Bump RN to 0.85.0 stable by @MatiPl01 in #9233
• fix: animation cancellation race condition by @Nodonisko in #9235
• fix: animation cancellation race condition missing code by @tjzel in #9242
• Change UI runtime slow animations invocation pattern by @tshmieldev in #9205
• chore: Remove no longer used StaticPropsRegistry methods and props by @MatiPl01 in #9226
• chore: Remove unused css code by @MatiPl01 in #9227
• fix: Incorrect CSS props reverting on CSS transition detach by @MatiPl01 in #9220
• feat: Strict TS types in LA withInitialValues method by @MatiPl01 in #9232
• fix: Freeze example crash and different timings by @MatiPl01 in #9247
• feat: Add support for separate transform props in LA initial values config by @MatiPl01 in #9237
• refactor: decouple raf and events by @tjzel in #9244
• feat(Reanimated): Export NativeEventsManager by @j-piasecki in #8655
• feat: adds withTargetValues modifier to default layout animations by @PiotrWszolek in #8848
• chore(Reanimated): jest tests for useFrameCallback by @tjzel in #9255
• docs: Remove withInitialValues for layout transitions by @MatiPl01 in #9258
• fix: Remove withInitialValues and withTargetValues from layout transitions by @MatiPl01 in #9259
• feat: Update initial value of shared value by @pranko17 in #8782
• chore(Reanimated): add lint step to disallow worklets includes by @tjzel in #9262
• docs: Add new types of initial values in layout animation configs by @MatiPl01 in #9257
• docs: Add withTargetValues to Layout Animations docs by @PiotrWszolek in #9168
• fix: Fix handling falsy values in jestUtils getCurrentStyle by @edkimmel in #7494
• fix: Unistyles flattening regression in 4.3.0 by @MatiPl01 in #9284
• fix(Reanimated): not flushing updates without mapper runs by @tjzel in #9270
• fix(Reanimated): useScrollOffset on renderScrollComponent by @tjzel in #9286
• chore: Extract CSS loop to the separate OperationsLoop class by @MatiPl01 in #9285
• Chore(Reanimated): reanimatedmoduleproxy refactor by @tshmieldev in #9342
• fix(Reanimated): registries race conditions by @tjzel in #9323
• Remove checks for new arch enabled by @tomekzaw in #9311
• feat: Add short-circuit for scheduleOnUI called from the UI thread on Android by @MatiPl01 in #9343
• feat: Add LoopOperation interface and operation-based scheduling primitives by @MatiPl01 in #9346
• docs: remove outdated "Debugging worklets" guide by @tomekzaw in #9355
• Use REACT_NATIVE_VERSION_MINOR provided by React Native instead of custom definition by @tomekzaw in #8412
• fix: Attempt to fix EXC_BAD_ACCESS in ReanimatedModuleProxy::performOperations during AnimationFrameBatchinator::flush by @MatiPl01 in #9308
• Remove legacy CDP debugger setup via HermesExecutorRuntimeAdapter by @tomekzaw in #9356
• chore(Reanimated)...

Key changes

Support for cross-runtime Promises

Now functions that return a promise like runOnRuntimeAsync can be used on all runtimes in Bundle Mode, not only the RN Runtime.
The code responsible for memory-management of JavaScript callbacks in C++ was overhauled to support this, which should reduce
the memory imprint and stability of long-held callbacks in brownfield app.

• feat(Worklets): cross-runtime promise handling in Bundle Mode by @tjzel in #9451
• refactor(Worklets): remoteFunction memory model by @tjzel in #9272

Uniform Shareable hosting

Shareables can now be hosted on any runtime, not only the UI Runtime.

• Added shareable support outside UI runtime by @tshmieldev in #9391

DX improvements

• Passing a local function to scheduleOnRN no longer crashes the app in C++ but throws an actionable error in JavaScript.

  • feat(Worklets): actionable error when passing local function to scheduleOnRN by @tjzel in #9386

• We append an asynchronous stacktrace to error thrown in Worklets for easier debugging.
  This is an opt-out feature that can be disabled with ENABLE_CROSS_RUNTIME_STACK_TRACES static feature flag.

  • Add RN runtime error traces to errors from UI runtime by @tshmieldev in #9280

• Console implementation in Bundle Mode now prints objects exactly the same way on Worklet Runtimes as on the RN Runtime.

  • Added native logging behavior to worklets runtime by @tshmieldev in #9201

Other changes

• feat(Worklets): Serializable regexp by @tshmieldev in #9494
• feat(Worklets): respect relative requires in worklets by @tjzel in #9486
• feat(Worklets): simplified Bundle Mode setup vol2 by @tjzel in #9465
• feat(Worklets): add native ArrayBuffer serialization support and explicitly deprecate _createSerializable by @tjzel in #9464
• feat(Worklets): native Error serialization by @tjzel in #9452
• feat(Worklets): use __RUNTIME_NAME for better error messages by @tjzel in #9410
• migrated worklets from java to kotlin by @tshmieldev in #9130
• fix(Worklets): misplaced else when cloning remote function by @tjzel in #9141
• fix(Worklets): wrong config object in .podspec by @tjzel in #9169
• chore(Worklets): improve async scheduling API error messages by @tjzel in #9183
• fix: Worklets x Reanimated compatibility CI by @tjzel in #9188
• refactor(Worklets): load unpackers with JSI by @tjzel in #8984
• refactor(Worklets): two-step initialization by @tjzel in #9203
• Replaced WorkletsError and ReanimatedError with lint rule by @tshmieldev in #9243
• fix(Worklets): duplicate definitions to call microtasks by @tjzel in #9245
• Refactored JSIWorkletsModuleProxy to not inherit from HostObject by @tshmieldev in #9252
• [fix]ed installUnpackers being called in bundleMode by @tshmieldev in #9283
• CallGuard in cpp, added support for worklet batching by @tshmieldev in #9313
• Added tests for bundle mode in babel plugin by @tshmieldev in #9318
• fix(Worklets): shareable deadlock by @tjzel in #9321
• chore(Worklets): removed stackDetails from bundleMode by @tshmieldev in #9331
• chore(Worklets): remove duplicate RNRuntime decoration by @tjzel in #9332
• chore(Worklets) Changed scheduleOnUI to schedule in helper by @tshmieldev in #9376
• chore(Worklets): documented stack trace flag by @tshmieldev in #9378
• chore(Worklets): various cleanups by @tjzel in #9387
• chore(Worklets): update deprecated API snippets by @tjzel in #9392
• Worklets: fixed memleak in shareable and serializable by @tshmieldev in #9393
• chore(Worklets): renamed cleanupIfRuntimeExists by @tshmieldev in #9426
• chore(Worklets): cleaned up ts createWorkletRuntime interface by @tshmieldev in #9427
• fix(Worklets): remove unused hermes/hermes.h include in UnpackerLoader.h by @tomekzaw in #9448
• chore(Worklets): serialization code nits by @tjzel in #9453
• fix(Worklets): repair NDEBUG-only build error in SerializableRemoteFunction by @tomekzaw in #9456
• chore(Worklets): add recent expo issues to troubleshooting page by @tshmieldev in #9460
• refactor(Worklets): add hostRuntimeId to JSIWorkletsModuleProxy by @tjzel in #9461
• chore(Worklets): throw when serializing promises by @tjzel in #9468
• Symbol serializable hotfix by @tshmieldev in #9476
• fix(Worklets): unused lambda capture in release Android build by @tomekzaw in #9480
• chore(Worklets): remove unnecessary CI-s by @tshmieldev in #9484
• fix(Worklets): eager imports issue by @tjzel in #9488

New Contributors

• @tshmieldev made their first contribution in #9130
• @avibega23 made their first contribution in #9153
• @mobinni made their first contribution in #9052
• @pkfms made their first contribution in #9154
• @GrzywN made their first contribution in #9175
• @PiotrWszolek made their first contribution in #8848
• @pranko17 made their first contribution in #8782
• @edkimmel made their first contribution in #7494
• @ashfurrow made their first contribution in #9162
• @elliottkember made their first contribution in #9466

Full Changelog: worklets-0.8.3...worklets-0.9.1

What's Changed

• cherry-pick(Reanimated): Incorrect CSS props reverting on CSS transition detach (#9220) by @MatiPl01 in #9288
• cherry-pick(Reanimated): Fix animation cancellation race condition missing code (#9242) by @MatiPl01 in #9289
• cherry-pick(4.3-stable): workflow for OIDC publishing (#9095) by @tjzel in #9298
• cherry-pick(4.3-stable): useScrollOffset on renderScrollComponent (#9286) by @tjzel in #9299
• cherry-pick(Reanimated): Fix Unistyles flattening regression in 4.3.0 (#9284) by @MatiPl01 in #9301
• cherry-pick(4.3-stable): fix registries race conditions (#9323) by @tjzel in #9349
• release(Reanimated): 4.3.1 by @tjzel in #9353

Full Changelog: 4.3.0...4.3.1

Full Changelog: worklets-0.8.2...worklets-0.8.3

What's Changed

• release(Worklets): 0.8.3 by @tjzel in #9339

Full Changelog: worklets-0.8.2...worklets-0.8.3

What's Changed

• cherry-pick(worklets-0.8-stable): shareable deadlock (#9321) by @tjzel in #9335

Full Changelog: worklets-0.8.1...worklets-0.8.2

Key changes

CSS SVG Animations

CSS animations now support animating SVG components and their properties, including Path, Image, LinearGradient, RadialGradient, Pattern and Text. This includes support for animating the d property of Path components with a special handling for path morphing.

• feat: Implement CSS SVG Polyline by @wisniewskij in #9003
• feat: Implement CSS SVG Polygon by @MatiPl01 in #9008
• feat: Support % length values in SVG CSS animations by @MatiPl01 in #9011
• Add css SVG Path parser and normalizer by @wisniewskij in #8709
• CSS SVGPath interpolation by @wisniewskij in #8710
• Enable support for SVGImage in CSS by @wisniewskij in #8830
• feat: Add support for SVG Pattern component in SVG animations by @MatiPl01 in #9041
• CSS SVGRadialGradient support by @wisniewskij in #8871
• CSS SVGLinearGradient support by @wisniewskij in #8917
• Enable support for SVGText in CSS by @wisniewskij in #9022

Shared Value re-implementation

Shared Value internal implementation changed - now it uses Shareable type from react-native-worklets as its internal value container. That means you can finally use Shared Values from other Worklet Runtimes than just the UI Runtime. Also USE_SYNCHRONIZABLE_IN_MUTABLE optimization feature flag is now enabled by default.

• feat(Reanimated): enable Synchronizable in Mutable by default by @tjzel in #9068
• feat(Reanimated): use Shareable for Mutables by @tjzel in #9004

Animated Styles type changes

TypeScript type of Animated Styles now makes it impossible to accidentally pass them to non-animated components. This replaces previous runtime-check for this kind of mistake, which proved to be prone to false positives.

• refactor: make AnimatedStyle type fail on non-animated components by @tjzel in #8990

Fixes

• fix: use native processTransformOrigin instead of web version by @maxpotemkin in #8738
• fix: prefab headers locations by @tjzel in #8747
• fix: Proper support for nested animatedProps objects and correct cleanup by @MatiPl01 in #8726
• fix(web): Support originX and originY in layout animations by @choi138 in #8733
• fix: Web entering animations triggered on view exiting by @MatiPl01 in #8772
• fix: Animation names array order updates on keyframes order change by @MatiPl01 in #8777
• fix: Infinity parsing in web CSS animationIterationCount by @MatiPl01 in #8787
• fix: FORCE_REACT_RENDER_FOR_SETTLED_ANIMATIONS feature flag crashes by @MatiPl01 in #8822
• fix: SharedValue.modify strict type definition by @huextrat in #8846
• fix: FORCE_REACT_RENDER_FOR_SETTLED_ANIMATIONS incorrect color alphas by @DouweBos in #8841
• fix: Guard for undefined style in Jest utils by @msynowski in #8878
• fix: Stop passing nativeID to component in jest unit tests by @MatiPl01 in #8881
• Fix the issue with next.js throwing errors while hydrating by @5ZYSZ3K in #8869
• fix: useHandler not working on web without babel plugin by @MatiPl01 in #8883
• fix: noplugin option being ignored in the web-example by @MatiPl01 in #8933
• fix: CSS SVGPath android parsing bugfix by @wisniewskij in #8918
• fix: free __cxa_demangle allocations in SingleInstanceChecker by @jingjing2222 in #8964
• fix: pass shouldPersistRemote to cloneObjectProperties by @aljadan in #8995
• fix: Fix native matchVersion not allowing patch version mismatches by @kitten in #9018
• fix: CSS transitions not working when a prop is added or removed by @MatiPl01 in #9014
  react-native-reanimated/pull/9015
• fix: static frameworks missing header paths by @tjzel in #9035
• Fix sync props back to React mechanism by @tomekzaw in #9046
• Fix: Add missing initialization in SVG Path by @wisniewskij in #9058
• fix: RN 0.81 TS errors by @tjzel in #9059
• fix: CSS animation box-shadow crashes by @MatiPl01 in #9065
• fix: CSS transition flickering on transitionProperty change by @MatiPl01 in #9120
• fix: guard against null styleProps in PropsRegistry GC by @mobinni in #9052
• fix - passing negative values to filter crashes on iOS by @intergalacticspacehighway in #9155
• [Android] Fix commits during drawing by @bartlomiejbloniarz in #9072
• perf: Don't trigger CSS transition for props with effective duration 0 by @MatiPl01 in #9118
• chore: useHandler reimplementation by @MatiPl01 in #9090

Refactors

• refactor(Reanimated): use own SingleInstanceChecker by @tjzel in #8935
• refactor: move events to Reanimated by @tjzel in #8934
• refactor(Reanimated): use own JSIUtils by @tjzel in #8938
• refactor: Rename processOpacity to processPercentage by @wisniewskij in #8947
• Extract applySynchronousUpdates from performOperations by @bartlomiejbloniarz in #9078
• Replace isInt with isNumber in synchronous props check by @tomekzaw in #9113

Chores

• Add _beginSection and _endSection JSI bindings for systraces by @tomekzaw in #9101
• Add _startProfiling and _stopProfiling JSI bindings for Hermes sampling profiler by @tomekzaw in #9102
• feat: Common fallback style props builder for any unsupported component by @MatiPl01 in #8989
• feat: peer dependencies validation by @tjzel in #9019
• feat: stable API versioning checks by @tjzel in #9105
• chore: modernize build.gradle scripts by @tjzel in #8707
• chore: consider new arch always enabled in react-native 0.82+ by @gabrieldonadel in #8771
• chore: Change props overriding behavior in the props builder by @MatiPl01 in #8877
• chore: Change folly::dynamic to jsi::Value in updateKeyframes for CSS transitions by @MatiPl01 in #8982
• chore: bump gradle versions by @tjzel in #8994
• chore: only consider latest patch in compatibility tables by @tjzel in #9142
• chore: unpin dependencies by @tjzel in #9143
• chore(Rea): migrate to RCTModernEventEmitter by @tjzel in #9033
• chore: Remove unused `has...

What's Changed

• [cherry-pick][4.2] Fix commits during the Android draw pass by @bartlomiejbloniarz in #9123
• cherry-pick(4.2-stable): peer dependencies validation (#9019) by @tjzel in #9136
• chore(4.2-stable): bump accepted worklets by @tjzel in #9137

Full Changelog: 4.2.2...4.2.3

What's Changed

• [cherry-pick][4.1] Fix commits during the Android draw pass by @bartlomiejbloniarz in #9124
• chore(4.1-stable): bump accepted worklets by @tjzel in #9135
• cherry-pick(4.1-stable): peer dependencies validation (#9019) by @tjzel in #9134

Full Changelog: 4.1.6...4.1.7

What's Changed

• cherry-pick(0.8-stable): misplaced else when cloning remote function (#9141) by @tjzel in #9144
• release(Worklets): 0.8.1 by @tjzel in #9146

Full Changelog: worklets-0.8.0...worklets-0.8.1

Key changes

Features:

• New shared memory type, Shareable, a building block for Reanimated's Shared Value implementation. See Docs and blogpost for more details.

  • feat(Worklets): implement Shareable type by @tjzel in #8673

• Stable C++ API bindings for libraries to use.

  • feat(Worklets): stable api bindings for Reanimated by @tjzel in #8996

• New runOnRuntimeSync API - allows you to schedule a worklet on any Worklet Runtime synchronously. Docs

  • feat(Worklets): runOnRuntimeSync by @skusnierz in #8224

• New scheduling APIs, scheduleOnRuntimeWithId, runOnRuntimeSyncWithId - allows you to schedule worklets on Worklet Runtimes just by knowing their id. Docs

  • feat(Worklets): dispatch to Worklet Runtimes from id by @tjzel in #8991

• New runOnRuntimeAsync API - allows you to schedule a worklet on any Worklet Runtime asynchronously and return a promise with the result. Docs

  • feat: add runOnRuntimeAsync by @riteshshukla04 in #8901

• New useful API shorthands for checking current runtime context. Docs

  • feat(Worklets): better runtimeKind checking API by @tjzel in #8758

• New Worklets Babel plugin option, strictGlobal, that prevents accidental captures of variables from global scope in worklets. Docs

  • feat(Worklets): Babel plugin strict global option by @tjzel in #8857

• You can now schedule worklets on Worklet Runtimes even outside of Bundle Mode, but with some limitations. There are no limitations when using the Bundle Mode.

  • feat(Worklets): limited scheduling on worklet runtimes outside of bundle mode by @tjzel in #9092

Bundle mode improvements:

• You no longer need to patch React Native to use Bundle Mode, meaning that you can use pre-built React Native for faster compilation.

  • feat(Worklets): run Bundle Mode without patches to React Native by @tjzel in #8744

• You no longer need to re-compile Worklets when switching between Bundle Mode and non-Bundle Mode (metro cache reset is still required).

  • feat(Worklets): always compile bundle mode symbols by @tjzel in #9064

• (experimental) You can now run network request in Bundle Mode Docs

  • feat(Worklets): Worklet Runtime ios fetch by @tjzel in #8410
  • feat(Worklets): android fetch by @tjzel in #8850

Docs:

• Documentation explaining what are closures in context of worklets, how they work and how to use them. Docs
  • feat(Worklets): docs about closures by @tjzel in #8889

Other changes

• chore: modernize build.gradle scripts by @tjzel in #8707
• chore(Worklets): Bundle Mode patches for 0.83.0 by @tjzel in #8737
• fix: prefab headers locations by @tjzel in #8747
• fix(Worklets): Add HERMES_V1_ENABLED flag to iOS podspec for Hermes V1 compatibility by @kimchi-developer in #8754
• feat(Worklets): docs for plugin types by @tjzel in #8633
• fix(Worklets): missing sideEffects property by @tjzel in #8760
• chore(Worklets): cleanup metro overrides for bundle mode by @tjzel in #8851
• refactor(Worklets): obtain BundleMode flag from static feature flags by @tjzel in #8853
• refactor(Worklets): dont use @react-native/babel-preset for unit tests by @tjzel in #8862
• fix(Worklets): Synchronizable serialization for objects outside of Bundle Mode by @tjzel in #8887
• chore(Worklets): rename __generatedWorklets dir by @tjzel in #8894
• feat(Worklets): docs for new bundle mode by @tjzel in #8759
• fix(Worklets): false-positive inlineStyles warning on computed [value] by @tjzel in #8897
• fix: Simplify run-loop and always attach JNI on Android by @mrousavy in #8905
• Fix bundle mode on windows by @OrfeasZ in #8910
• fix(worklets): avoid HERMES_V1_ENABLED macro redefinition on RN 0.84+ by @kimchi-developer in #8908
• chore(Worklets): fix runAsync mock signature by @tjzel in #8916
• refactor(Worklets): move serializable factories by @tjzel in #8560
• feat: docs for runOnRuntimeAsync by @riteshshukla04 in #8911
• fix: sidebar title of runtimeAsync by @riteshshukla04 in #8921
• docs(Worklets): add gtm by @p-malecki in #8937
• docs: add gtm by @p-malecki in #8936
• Remove workaround for dynamic frameworks by @tomekzaw in #8927
• chore(Worklets): compatibility docs by @tjzel in #8971
• fix: free __cxa_demangle allocations in SingleInstanceChecker by @jingjing2222 in #8964
• fix(Worklets): pulling native implementation for Jest tests by @tjzel in #8988
• chore(Worklets): cleanup dispatch functions and tests by @tjzel in #9006
• [docs] Fix scheduleOnRN call to remove extra invocation by @piaskowyk in #9017
• refactor(Worklets): always spin AnimationFrameQueue by @tjzel in #8900
• fix: Fix native matchVersion not allowing patch version mismatches by @kitten in #9018
• chore(Worklets): install serializer on UI Runtime by @tjzel in #9024
• chore(Worklets): merge isSynchronizable impl by @tjzel in #9027
• chore(Worklets): stabilize Serializable enum by @tjzel in #9025
• chore(Worklets): add RuntimeId type alias by @tjzel in #9026
• chore(Worklets): export unpackers in prod env by @tjzel in #9029
• fix: Reanimated synchronous events by @tjzel in #9057
• chore(Worklets): update createWorkletRuntime docs by @tjzel in #9030
• fix(Worklets): cascade raf callbacks with reanimated by @tjzel in #9080
• feat: stable API versioning checks by @tjzel in #9105
• feat: Reanimated x Worklets compilation compatibility CI by @tjzel in #8997
• fix(Worklets): remote function re-serialization by @tjzel in #9115
• chore(Worklets): update algolia keys by @tjzel in #9128
• release(Worklets): 0.8.0 by @tjzel in #9131

New C...