Releases: facebook/react
18.3.1 (April 26, 2024)
- Export
act
fromreact
f1338f
18.3.0 (April 25, 2024)
This release is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19.
Read the React 19 Upgrade Guide for more info.
React
- Allow writing to
this.refs
to support string ref codemod 909071 - Warn for deprecated
findDOMNode
outside StrictMode c3b283 - Warn for deprecated
test-utils
methods d4ea75 - Warn for deprecated Legacy Context outside StrictMode 415ee0
- Warn for deprecated string refs outside StrictMode #25383
- Warn for deprecated
defaultProps
for function components #25699 - Warn when spreading
key
#25697 - Warn when using
act
fromtest-utils
d4ea75
React DOM
18.2.0 (June 14, 2022)
React DOM
- Provide a component stack as a second argument to
onRecoverableError
. (@gnoff in #24591) - Fix hydrating into
document
causing a blank page on mismatch. (@gnoff in #24523) - Fix false positive hydration errors with Suspense. (@gnoff in #24480 and @acdlite in #24532)
- Fix ignored
setState
in Safari when adding an iframe. (@gaearon in #24459)
React DOM Server
- Pass information about server errors to the client. (@salazarm and @gnoff in #24551 and #24591)
- Allow to provide a reason when aborting the HTML stream. (@gnoff in #24680)
- Eliminate extraneous text separators in the HTML where possible. (@gnoff in #24630)
- Disallow complex children inside
<title>
elements to match the browser constraints. (@gnoff in #24679) - Fix buffering in some worker environments by explicitly setting
highWaterMark
to0
. (@jplhomer in #24641)
Server Components (Experimental)
18.1.0 (April 26, 2022)
React DOM
- Fix the false positive warning about
react-dom/client
when using UMD bundle. (@alireza-molaee in #24274) - Fix
suppressHydrationWarning
to work in production too. (@gaearon in #24271) - Fix
componentWillUnmount
firing twice inside of Suspense. (@acdlite in #24308) - Fix some transition updates being ignored. (@acdlite in #24353)
- Fix
useDeferredValue
causing an infinite loop when passed an unmemoized value. (@acdlite in #24247) - Fix throttling of revealing Suspense fallbacks. (@sunderls in #24253)
- Fix an inconsistency in whether the props object is the same between renders. (@Andarist and @acdlite in #24421)
- Fix a missing warning about a
setState
loop inuseEffect
. (@gaearon in #24298) - Fix a spurious hydration error. (@gnoff in #24404)
- Warn when calling
setState
inuseInsertionEffect
. (@gaearon in #24295) - Ensure the reason for hydration errors is always displayed. (@gaearon in #24276)
React DOM Server
- Fix escaping for the
bootstrapScriptContent
contents. (@gnoff in #24385) - Significantly improve performance of
renderToPipeableStream
. (@gnoff in #24291)
ESLint Plugin: React Hooks
- Fix false positive errors with a large number of branches. (@scyron6 in #24287)
- Don't consider a known dependency stable when the variable is reassigned. (@afzalsayed96 in #24343)
Use Subscription
18.0.0 (March 29, 2022)
Below is a list of all new features, APIs, deprecations, and breaking changes.
Read React 18 release post and React 18 upgrade guide for more information.
New Features
React
useId
is a new hook for generating unique IDs on both the client and server, while avoiding hydration mismatches. It is primarily useful for component libraries integrating with accessibility APIs that require unique IDs. This solves an issue that already exists in React 17 and below, but itβs even more important in React 18 because of how the new streaming server renderer delivers HTML out-of-order.startTransition
anduseTransition
let you mark some state updates as not urgent. Other state updates are considered urgent by default. React will allow urgent state updates (for example, updating a text input) to interrupt non-urgent state updates (for example, rendering a list of search results).useDeferredValue
lets you defer re-rendering a non-urgent part of the tree. It is similar to debouncing, but has a few advantages compared to it. There is no fixed time delay, so React will attempt the deferred render right after the first render is reflected on the screen. The deferred render is interruptible and doesn't block user input.useSyncExternalStore
is a new hook that allows external stores to support concurrent reads by forcing updates to the store to be synchronous. It removes the need foruseEffect
when implementing subscriptions to external data sources, and is recommended for any library that integrates with state external to React.useInsertionEffect
is a new hook that allows CSS-in-JS libraries to address performance issues of injecting styles in render. Unless youβve already built a CSS-in-JS library we donβt expect you to ever use this. This hook will run after the DOM is mutated, but before layout effects read the new layout. This solves an issue that already exists in React 17 and below, but is even more important in React 18 because React yields to the browser during concurrent rendering, giving it a chance to recalculate layout.
React DOM Client
These new APIs are now exported from react-dom/client
:
createRoot
: New method to create a root torender
orunmount
. Use it instead ofReactDOM.render
. New features in React 18 don't work without it.hydrateRoot
: New method to hydrate a server rendered application. Use it instead ofReactDOM.hydrate
in conjunction with the new React DOM Server APIs. New features in React 18 don't work without it.
Both createRoot
and hydrateRoot
accept a new option called onRecoverableError
in case you want to be notified when React recovers from errors during rendering or hydration for logging. By default, React will use reportError
, or console.error
in the older browsers.
React DOM Server
These new APIs are now exported from react-dom/server
and have full support for streaming Suspense on the server:
renderToPipeableStream
: for streaming in Node environments.renderToReadableStream
: for modern edge runtime environments, such as Deno and Cloudflare workers.
The existing renderToString
method keeps working but is discouraged.
Deprecations
react-dom
:ReactDOM.render
has been deprecated. Using it will warn and run your app in React 17 mode.react-dom
:ReactDOM.hydrate
has been deprecated. Using it will warn and run your app in React 17 mode.react-dom
:ReactDOM.unmountComponentAtNode
has been deprecated.react-dom
:ReactDOM.renderSubtreeIntoContainer
has been deprecated.react-dom/server
:ReactDOMServer.renderToNodeStream
has been deprecated.
Breaking Changes
React
- Automatic batching: This release introduces a performance improvement that changes to the way React batches updates to do more batching automatically. See Automatic batching for fewer renders in React 18 for more info. In the rare case that you need to opt out, wrap the state update in
flushSync
. - Stricter Strict Mode: In the future, React will provide a feature that lets components preserve state between unmounts. To prepare for it, React 18 introduces a new development-only check to Strict Mode. React will automatically unmount and remount every component, whenever a component mounts for the first time, restoring the previous state on the second mount. If this breaks your app, consider removing Strict Mode until you can fix the components to be resilient to remounting with existing state.
- Consistent useEffect timing: React now always synchronously flushes effect functions if the update was triggered during a discrete user input event such as a click or a keydown event. Previously, the behavior wasn't always predictable or consistent.
- Stricter hydration errors: Hydration mismatches due to missing or extra text content are now treated like errors instead of warnings. React will no longer attempt to "patch up" individual nodes by inserting or deleting a node on the client in an attempt to match the server markup, and will revert to client rendering up to the closest
<Suspense>
boundary in the tree. This ensures the hydrated tree is consistent and avoids potential privacy and security holes that can be caused by hydration mismatches. - Suspense trees are always consistent: If a component suspends before it's fully added to the tree, React will not add it to the tree in an incomplete state or fire its effects. Instead, React will throw away the new tree completely, wait for the asynchronous operation to finish, and then retry rendering again from scratch. React will render the retry attempt concurrently, and without blocking the browser.
- Layout Effects with Suspense: When a tree re-suspends and reverts to a fallback, React will now clean up layout effects, and then re-create them when the content inside the boundary is shown again. This fixes an issue which prevented component libraries from correctly measuring layout when used with Suspense.
- New JS Environment Requirements: React now depends on modern browsers features including
Promise
,Symbol
, andObject.assign
. If you support older browsers and devices such as Internet Explorer which do not provide modern browser features natively or have non-compliant implementations, consider including a global polyfill in your bundled application.
Scheduler (Experimental)
- Remove unstable
scheduler/tracing
API
Notable Changes
React
- Components can now render
undefined
: React no longer throws if you returnundefined
from a component. This makes the allowed component return values consistent with values that are allowed in the middle of a component tree. We suggest to use a linter to prevent mistakes like forgetting areturn
statement before JSX. - In tests,
act
warnings are now opt-in: If you're running end-to-end tests, theact
warnings are unnecessary. We've introduced an opt-in mechanism so you can enable them only for unit tests where they are useful and beneficial. - No warning about
setState
on unmounted components: Previously, React warned about memory leaks when you callsetState
on an unmounted component. This warning was added for subscriptions, but people primarily run into it in scenarios where setting state is fine, and workarounds make the code worse. We've removed this warning. - No suppression of console logs: When you use Strict Mode, React renders each component twice to help you find unexpected side effects. In React 17, we've suppressed console logs for one of the two renders to make the logs easier to read. In response to community feedback about this being confusing, we've removed the suppression. Instead, if you have React DevTools installed, the second log's renders will be displayed in grey, and there will be an option (off by default) to suppress them completely.
- Improved memory usage: React now cleans up more internal fields on unmount, making the impact from unfixed memory leaks that may exist in your application code less severe.
React DOM Server
renderToString
: Will no longer error when suspending on the server. Instead, it will emit the fallback HTML for the closest<Suspense>
boundary and then retry rendering the same content on the client. It is still recommended that you switch to a streaming API likerenderToPipeableStream
orrenderToReadableStream
instead.renderToStaticMarkup
: Will no longer error when suspending on the server. Instead, it will emit the fallback HTML for the closest<Suspense>
boundary and retry rendering on the client.
All Changes
React
17.0.2 (March 22, 2021)
React DOM
- Remove an unused dependency to address the
SharedArrayBuffer
cross-origin isolation warning. (@koba04 and @bvaughn in #20831, #20832, and #20840)
Artifacts
- react: https://unpkg.com/react@17.0.2/umd/
- react-art: https://unpkg.com/react-art@17.0.2/umd/
- react-dom: https://unpkg.com/react-dom@17.0.2/umd/
- react-is: https://unpkg.com/react-is@17.0.2/umd/
- react-test-renderer: https://unpkg.com/react-test-renderer@17.0.2/umd/
- scheduler: https://unpkg.com/scheduler@0.20.2/umd/
17.0.1 (October 22, 2020)
17.0.0 (October 20, 2020)
Today, we are releasing React 17!
Learn more about React 17 and how to update to it on the official React blog.
React
- Add
react/jsx-runtime
andreact/jsx-dev-runtime
for the new JSX transform. (@lunaruan in #18299) - Build component stacks from native error frames. (@sebmarkbage in #18561)
- Allow to specify
displayName
on context for improved stacks. (@eps1lon in #18224) - Prevent
'use strict'
from leaking in the UMD bundles. (@koba04 in #19614) - Stop using
fb.me
for redirects. (@cylim in #19598)
React DOM
- Delegate events to roots instead of
document
. (@trueadm in #18195 and others) - Clean up all effects before running any next effects. (@bvaughn in #17947)
- Run
useEffect
cleanup functions asynchronously. (@bvaughn in #17925) - Use browser
focusin
andfocusout
foronFocus
andonBlur
. (@trueadm in #19186) - Make all
Capture
events use the browser capture phase. (@trueadm in #19221) - Don't emulate bubbling of the
onScroll
event. (@gaearon in #19464) - Throw if
forwardRef
ormemo
component returnsundefined
. (@gaearon in #19550) - Remove event pooling. (@trueadm in #18969)
- Stop exposing internals that wonβt be needed by React Native Web. (@necolas in #18483)
- Attach all known event listeners when the root mounts. (@gaearon in #19659)
- Disable
console
in the second render pass of DEV mode double render. (@sebmarkbage in #18547) - Deprecate the undocumented and misleading
ReactTestUtils.SimulateNative
API. (@gaearon in #13407) - Rename private field names used in the internals. (@gaearon in #18377)
- Don't call User Timing API in development. (@gaearon in #18417)
- Disable console during the repeated render in Strict Mode. (@sebmarkbage in #18547)
- In Strict Mode, double-render components without Hooks too. (@eps1lon in #18430)
- Allow calling
ReactDOM.flushSync
during lifecycle methods (but warn). (@sebmarkbage in #18759) - Add the
code
property to the keyboard event objects. (@bl00mber in #18287) - Add the
disableRemotePlayback
property forvideo
elements. (@tombrowndev in #18619) - Add the
enterKeyHint
property forinput
elements. (@eps1lon in #18634) - Warn when no
value
is provided to<Context.Provider>
. (@charlie1404 in #19054) - Warn when
memo
orforwardRef
components returnundefined
. (@bvaughn in #19550) - Improve the error message for invalid updates. (@JoviDeCroock in #18316)
- Exclude forwardRef and memo from stack frames. (@sebmarkbage in #18559)
- Improve the error message when switching between controlled and uncontrolled inputs. (@vcarl in #17070)
- Keep
onTouchStart
,onTouchMove
, andonWheel
passive. (@gaearon in #19654) - Fix
setState
hanging in development inside a closed iframe. (@gaearon in #19220) - Fix rendering bailout for lazy components with
defaultProps
. (@jddxf in #18539) - Fix a false positive warning when
dangerouslySetInnerHTML
isundefined
. (@eps1lon in #18676) - Fix Test Utils with non-standard
require
implementation. (@just-boris in #18632) - Fix
onBeforeInput
reporting an incorrectevent.type
. (@eps1lon in #19561) - Fix
event.relatedTarget
reported asundefined
in Firefox. (@claytercek in #19607) - Fix "unspecified error" in IE11. (@hemakshis in #19664)
- Fix rendering into a shadow root. (@Jack-Works in #15894)
- Fix
movementX/Y
polyfill with capture events. (@gaearon in #19672) - Use delegation for
onSubmit
andonReset
events. (@gaearon in #19333) - Improve memory usage. (@trueadm in #18970)
React DOM Server
- Make
useCallback
behavior consistent withuseMemo
for the server renderer. (@alexmckenley in #18783) - Fix state leaking when a function component throws. (@pmaccart in #19212)
React Test Renderer
- Improve
findByType
error message. (@henryqdineen in #17439)
Concurrent Mode (Experimental)
- Revamp the priority batching heuristics. (@acdlite in #18796)
- Add the
unstable_
prefix before the experimental APIs. (@acdlite in #18825) - Remove
unstable_discreteUpdates
andunstable_flushDiscreteUpdates
. (@trueadm in #18825) - Remove the
timeoutMs
argument. (@acdlite in #19703) - Disable
<div hidden />
prerendering in favor of a different future API. (@acdlite in #18917) - Add
unstable_expectedLoadTime
to Suspense for CPU-bound trees. (@acdlite in #19936) - Add an experimental
unstable_useOpaqueIdentifier
Hook. (@lunaruan in #17322) - Add an experimental
unstable_startTransition
API. (@rickhanlonii in #19696) - Using
act
in the test renderer no longer flushes Suspense fallbacks. (@acdlite in #18596) - Use global render timeout for CPU Suspense. (@sebmarkbage in #19643)
- Clear the existing root content before mounting. (@bvaughn in #18730)
- Fix a bug with error boundaries. (@acdlite in #18265)
- Fix a bug causing dropped updates in a suspended tree. (@acdlite in #18384 and #18457)
- Fix a bug causing dropped render phase updates. (@acdlite in #18537)
- Fix a bug in Suspens...
16.14.0 (October 14, 2020)
React
- Add support for the new JSX transform. (@lunaruan in #18299)
15.7.0 (October 14, 2020)
React
- Backport support for the new JSX transform to 15.x. (@lunaruan in #18299 and @gaearon in #20024)