18.2.0 (June 14, 2022)
- Provide a component stack as a second argument to
onRecoverableError. (@gnoff in #24591)
- Fix hydrating into
documentcausing a blank page on mismatch. (@gnoff in #24523)
- Fix false positive hydration errors with Suspense. (@gnoff in #24480 and @acdlite in #24532)
- Fix ignored
setStatein 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
0. (@jplhomer in #24641)
Server Components (Experimental)
18.1.0 (April 26, 2022)
- Fix the false positive warning about
react-dom/clientwhen using UMD bundle. (@alireza-molaee in #24274)
suppressHydrationWarningto work in production too. (@gaearon in #24271)
componentWillUnmountfiring twice inside of Suspense. (@acdlite in #24308)
- Fix some transition updates being ignored. (@acdlite in #24353)
useDeferredValuecausing 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
useEffect. (@gaearon in #24298)
- Fix a spurious hydration error. (@gnoff in #24404)
- Warn when calling
useInsertionEffect. (@gaearon in #24295)
- Ensure the reason for hydration errors is always displayed. (@gaearon in #24276)
React DOM Server
- Fix escaping for the
bootstrapScriptContentcontents. (@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)
18.0.0 (March 29, 2022)
useIdis 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 it’s even more important in React 18 because of how the new streaming server renderer delivers HTML out-of-order.
useTransitionlet 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).
useDeferredValuelets 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.
useSyncExternalStoreis a new hook that allows external stores to support concurrent reads by forcing updates to the store to be synchronous. It removes the need for
useEffectwhen implementing subscriptions to external data sources, and is recommended for any library that integrates with state external to React.
useInsertionEffectis a new hook that allows CSS-in-JS libraries to address performance issues of injecting styles in render. Unless you’ve already built a CSS-in-JS library we don’t 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
createRoot: New method to create a root to
unmount. Use it instead of
ReactDOM.render. New features in React 18 don't work without it.
hydrateRoot: New method to hydrate a server rendered application. Use it instead of
ReactDOM.hydratein conjunction with the new React DOM Server APIs. New features in React 18 don't work without it.
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
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.
renderToString method keeps working but is discouraged.
ReactDOM.renderhas been deprecated. Using it will warn and run your app in React 17 mode.
ReactDOM.hydratehas been deprecated. Using it will warn and run your app in React 17 mode.
ReactDOM.unmountComponentAtNodehas been deprecated.
ReactDOM.renderSubtreeIntoContainerhas been deprecated.
ReactDOMServer.renderToNodeStreamhas been deprecated.
- 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
- 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
Object.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.
- Components can now render
undefined: React no longer throws if you return
undefinedfrom 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 a
returnstatement before JSX.
- In tests,
actwarnings are now opt-in: If you're running end-to-end tests, the
actwarnings 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
setStateon unmounted components: Previously, React warned about memory leaks when you call
setStateon 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 like
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.
17.0.2 (March 22, 2021)
- Remove an unused dependency to address the
SharedArrayBuffercross-origin isolation warning. (@koba04 and @bvaughn in #20831, #20832, and #20840)
- react: https://email@example.com/umd/
- react-art: https://firstname.lastname@example.org/umd/
- react-dom: https://email@example.com/umd/
- react-is: https://firstname.lastname@example.org/umd/
- react-test-renderer: https://email@example.com/umd/
- scheduler: https://firstname.lastname@example.org/umd/
17.0.1 (October 14, 2020)
17.0.0 (October 20, 2020)
Today, we are releasing React 17!
react/jsx-dev-runtimefor the new JSX transform. (@lunaruan in #18299)
- Build component stacks from native error frames. (@sebmarkbage in #18561)
- Allow to specify
displayNameon context for improved stacks. (@eps1lon in #18224)
'use strict'from leaking in the UMD bundles. (@koba04 in #19614)
- Stop using
fb.mefor redirects. (@cylim in #19598)
- Delegate events to roots instead of
document. (@trueadm in #18195 and others)
- Clean up all effects before running any next effects. (@bvaughn in #17947)
useEffectcleanup functions asynchronously. (@bvaughn in #17925)
- Use browser
onBlur. (@trueadm in #19186)
- Make all
Captureevents use the browser capture phase. (@trueadm in #19221)
- Don't emulate bubbling of the
onScrollevent. (@gaearon in #19464)
- Throw if
undefined. (@gaearon in #19550)
- Remove event pooling. (@trueadm in #18969)
- Stop exposing internals that won’t be needed by React Native Web. (@necolas in #18483)
- Attach all known event listeners when the root mounts. (@gaearon in #19659)
consolein the second render pass of DEV mode double render. (@sebmarkbage in #18547)
- Deprecate the undocumented and misleading
ReactTestUtils.SimulateNativeAPI. (@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.flushSyncduring lifecycle methods (but warn). (@sebmarkbage in #18759)
- Add the
codeproperty to the keyboard event objects. (@bl00mber in #18287)
- Add the
videoelements. (@tombrowndev in #18619)
- Add the
inputelements. (@eps1lon in #18634)
- Warn when no
valueis provided to
<Context.Provider>. (@charlie1404 in #19054)
- Warn when
undefined. (@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)
onWheelpassive. (@gaearon in #19654)
setStatehanging 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
undefined. (@eps1lon in #18676)
- Fix Test Utils with non-standard
requireimplementation. (@just-boris in #18632)
onBeforeInputreporting an incorrect
event.type. (@eps1lon in #19561)
undefinedin Firefox. (@claytercek in #19607)
- Fix "unspecified error" in IE11. (@hemakshis in #19664)
- Fix rendering into a shadow root. (@Jack-Works in #15894)
movementX/Ypolyfill with capture events. (@gaearon in #19672)
- Use delegation for
onResetevents. (@gaearon in #19333)
- Improve memory usage. (@trueadm in #18970)
React DOM Server
useCallbackbehavior consistent with
useMemofor the server renderer. (@alexmckenley in #18783)
- Fix state leaking when a function component throws. (@pmaccart in #19212)
React Test Renderer
Concurrent Mode (Experimental)
- Revamp the priority batching heuristics. (@acdlite in #18796)
- Add the
unstable_prefix before the experimental APIs. (@acdlite in #18825)
unstable_flushDiscreteUpdates. (@trueadm in #18825)
- Remove the
timeoutMsargument. (@acdlite in #19703)
<div hidden />prerendering in favor of a different future API. (@acdlite in #18917)
unstable_expectedLoadTimeto Suspense for CPU-bound trees. (@acdlite in #19936)
- Add an experimental
unstable_useOpaqueIdentifierHook. (@lunaruan in #17322)
- Add an experimental
unstable_startTransitionAPI. (@rickhanlonii in #19696)
actin 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)
15.7.0 (October 14, 2020)
0.14.10 (October 14, 2020)
16.13.1 (March 19, 2020)
- Fix bug in legacy mode Suspense where effect clean-up functions are not fired. This only affects users who use Suspense for data fetching in legacy mode, which is not technically supported. (@acdlite in #18238)
- Revert warning for cross-component updates that happen inside class render lifecycles (
shouldComponentUpdate, and so on). (@gaearon in #18330)
- react: https://email@example.com/umd/
- react-art: https://firstname.lastname@example.org/umd/
- react-dom: https://email@example.com/umd/
- react-is: https://firstname.lastname@example.org/umd/
- react-test-renderer: https://email@example.com/umd/
- scheduler: https://firstname.lastname@example.org/umd/