85ac253
feat: Add support for React 19 (#1367)Sourced from react's releases.
19.0.0 (December 5, 2024)
Below is a list of all new features, APIs, deprecations, and breaking changes. Read React 19 release post and React 19 upgrade guide for more information.
Note: To help make the upgrade to React 19 easier, we’ve published a react@18.3 release that is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19. We recommend upgrading to React 18.3.1 first to help identify any issues before upgrading to React 19.
New Features
React
- Actions:
startTransition
can now accept async functions. Functions passed tostartTransition
are called “Actions”. A given Transition can include one or more Actions which update state in the background and update the UI with one commit. In addition to updating state, Actions can now perform side effects including async requests, and the Action will wait for the work to finish before finishing the Transition. This feature allows Transitions to include side effects likefetch()
in the pending state, and provides support for error handling, and optimistic updates.useActionState
: is a new hook to order Actions inside of a Transition with access to the state of the action, and the pending state. It accepts a reducer that can call Actions, and the initial state used for first render. It also accepts an optional string that is used if the action is passed to a formaction
prop to support progressive enhancement in forms.useOptimistic
: is a new hook to update state while a Transition is in progress. It returns the state, and a set function that can be called inside a transition to “optimistically” update the state to expected final value immediately while the Transition completes in the background. When the transition finishes, the state is updated to the new value.use
: is a new API that allows reading resources in render. In React 19,use
accepts a promise or Context. If provided a promise,use
will suspend until a value is resolved.use
can only be used in render but can be called conditionally.ref
as a prop: Refs can now be used as props, removing the need forforwardRef
.- Suspense sibling pre-warming: When a component suspends, React will immediately commit the fallback of the nearest Suspense boundary, without waiting for the entire sibling tree to render. After the fallback commits, React will schedule another render for the suspended siblings to “pre-warm” lazy requests.
React DOM Client
<form> action
prop: Form Actions allow you to manage forms automatically and integrate withuseFormStatus
. When a<form> action
succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the newrequestFormReset
API.<button> and <input> formAction
prop: Actions can be passed to theformAction
prop to configure form submission behavior. This allows using different Actions depending on the input.useFormStatus
: is a new hook that provides the status of the parent<form> action
, as if the form was a Context provider. The hook returns the values:pending
,data
,method
, andaction
.- Support for Document Metadata: We’ve added support for rendering document metadata tags in components natively. React will automatically hoist them into the
<head>
section of the document.- Support for Stylesheets: React 19 will ensure stylesheets are inserted into the
<head>
on the client before revealing the content of a Suspense boundary that depends on that stylesheet.- Support for async scripts: Async scripts can be rendered anywhere in the component tree and React will handle ordering and deduplication.
- Support for preloading resources: React 19 ships with
preinit
,preload
,prefetchDNS
, andpreconnect
APIs to optimize initial page loads by moving discovery of additional resources like fonts out of stylesheet loading. They can also be used to prefetch resources used by an anticipated navigation.React DOM Server
- Added
prerender
andprerenderToNodeStream
APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. UnlikerenderToString
, they wait for data to load for HTML generation.React Server Components
- RSC features such as directives, server components, and server functions are now stable. This means libraries that ship with Server Components can now target React 19 as a peer dependency with a react-server export condition for use in frameworks that support the Full-stack React Architecture. The underlying APIs used to implement a React Server Components bundler or framework do not follow semver and may break between minors in React 19.x. See docs for how to support React Server Components.
Deprecations
- Deprecated:
element.ref
access: React 19 supports ref as a prop, so we’re deprecatingelement.ref
in favor ofelement.props.ref
. Accessing will result in a warning.react-test-renderer
: In React 19, react-test-renderer logs a deprecation warning and has switched to concurrent rendering for web usage. We recommend migrating your tests to@testinglibrary
.com/docs/react-testing-library/intro/) or@testingesting-library
.com/docs/react-native-testing-library/intro)Breaking Changes
React 19 brings in a number of breaking changes, including the removals of long-deprecated APIs. We recommend first upgrading to
18.3.1
, where we've added additional deprecation warnings. Check out the upgrade guide for more details and guidance on codemodding.React
- New JSX Transform is now required: We introduced a new JSX transform in 2020 to improve bundle size and use JSX without importing React. In React 19, we’re adding additional improvements like using ref as a prop and JSX speed improvements that require the new transform.
- Errors in render are not re-thrown: Errors that are not caught by an Error Boundary are now reported to window.reportError. Errors that are caught by an Error Boundary are reported to console.error. We’ve introduced
onUncaughtError
andonCaughtError
methods tocreateRoot
andhydrateRoot
to customize this error handling.- Removed:
propTypes
: UsingpropTypes
will now be silently ignored. If required, we recommend migrating to TypeScript or another type-checking solution.- Removed:
defaultProps
for functions: ES6 default parameters can be used in place. Class components continue to supportdefaultProps
since there is no ES6 alternative.- Removed:
contextTypes
andgetChildContext
: Legacy Context for class components has been removed in favor of thecontextType
API.
... (truncated)
Sourced from react's changelog.
19.0.0 (December 5, 2024)
Below is a list of all new features, APIs, deprecations, and breaking changes. Read React 19 release post and React 19 upgrade guide for more information.
Note: To help make the upgrade to React 19 easier, we’ve published a react@18.3 release that is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19. We recommend upgrading to React 18.3.1 first to help identify any issues before upgrading to React 19.
New Features
React
- Actions:
startTransition
can now accept async functions. Functions passed tostartTransition
are called “Actions”. A given Transition can include one or more Actions which update state in the background and update the UI with one commit. In addition to updating state, Actions can now perform side effects including async requests, and the Action will wait for the work to finish before finishing the Transition. This feature allows Transitions to include side effects likefetch()
in the pending state, and provides support for error handling, and optimistic updates.useActionState
: is a new hook to order Actions inside of a Transition with access to the state of the action, and the pending state. It accepts a reducer that can call Actions, and the initial state used for first render. It also accepts an optional string that is used if the action is passed to a formaction
prop to support progressive enhancement in forms.useOptimistic
: is a new hook to update state while a Transition is in progress. It returns the state, and a set function that can be called inside a transition to “optimistically” update the state to expected final value immediately while the Transition completes in the background. When the transition finishes, the state is updated to the new value.use
: is a new API that allows reading resources in render. In React 19,use
accepts a promise or Context. If provided a promise,use
will suspend until a value is resolved.use
can only be used in render but can be called conditionally.ref
as a prop: Refs can now be used as props, removing the need forforwardRef
.- Suspense sibling pre-warming: When a component suspends, React will immediately commit the fallback of the nearest Suspense boundary, without waiting for the entire sibling tree to render. After the fallback commits, React will schedule another render for the suspended siblings to “pre-warm” lazy requests.
React DOM Client
<form> action
prop: Form Actions allow you to manage forms automatically and integrate withuseFormStatus
. When a<form> action
succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the newrequestFormReset
API.<button> and <input> formAction
prop: Actions can be passed to theformAction
prop to configure form submission behavior. This allows using different Actions depending on the input.useFormStatus
: is a new hook that provides the status of the parent<form> action
, as if the form was a Context provider. The hook returns the values:pending
,data
,method
, andaction
.- Support for Document Metadata: We’ve added support for rendering document metadata tags in components natively. React will automatically hoist them into the
<head>
section of the document.- Support for Stylesheets: React 19 will ensure stylesheets are inserted into the
<head>
on the client before revealing the content of a Suspense boundary that depends on that stylesheet.- Support for async scripts: Async scripts can be rendered anywhere in the component tree and React will handle ordering and deduplication.
- Support for preloading resources: React 19 ships with
preinit
,preload
,prefetchDNS
, andpreconnect
APIs to optimize initial page loads by moving discovery of additional resources like fonts out of stylesheet loading. They can also be used to prefetch resources used by an anticipated navigation.React DOM Server
- Added
prerender
andprerenderToNodeStream
APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. UnlikerenderToString
, they wait for data to load for HTML generation.React Server Components
- RSC features such as directives, server components, and server functions are now stable. This means libraries that ship with Server Components can now target React 19 as a peer dependency with a react-server export condition for use in frameworks that support the Full-stack React Architecture. The underlying APIs used to implement a React Server Components bundler or framework do not follow semver and may break between minors in React 19.x. See docs for how to support React Server Components.
Deprecations
- Deprecated:
element.ref
access: React 19 supports ref as a prop, so we’re deprecatingelement.ref
in favor ofelement.props.ref
. Accessing will result in a warning.react-test-renderer
: In React 19, react-test-renderer logs a deprecation warning and has switched to concurrent rendering for web usage. We recommend migrating your tests to@testing-library/react
or@testing-library/react-native
Breaking Changes
React 19 brings in a number of breaking changes, including the removals of long-deprecated APIs. We recommend first upgrading to
18.3.1
, where we've added additional deprecation warnings. Check out the upgrade guide for more details and guidance on codemodding.React
- New JSX Transform is now required: We introduced a new JSX transform in 2020 to improve bundle size and use JSX without importing React. In React 19, we’re adding additional improvements like using ref as a prop and JSX speed improvements that require the new transform.
- Errors in render are not re-thrown: Errors that are not caught by an Error Boundary are now reported to window.reportError. Errors that are caught by an Error Boundary are reported to console.error. We’ve introduced
onUncaughtError
andonCaughtError
methods tocreateRoot
andhydrateRoot
to customize this error handling.- Removed:
propTypes
: UsingpropTypes
will now be silently ignored. If required, we recommend migrating to TypeScript or another type-checking solution.- Removed:
defaultProps
for functions: ES6 default parameters can be used in place. Class components continue to supportdefaultProps
since there is no ES6 alternative.
... (truncated)
e137890
[string-refs] cleanup string ref code (#31443)d1f0472
[string-refs] remove enableLogStringRefsProd flag (#31414)3dc1e48
Followup: remove dead test code from #30346
(#31415)07aa494
Remove enableRefAsProp feature flag (#30346)45804af
[flow] Eliminate usage of more than 1-arg
React.AbstractComponent
in React ...5636fad
[string-refs] log string ref from prod (#31161)b78a7f2
[rcr] Re-export useMemoCache in top level React namespace (#31139)4e9540e
[Fiber] Log the Render/Commit phases and the gaps in between (#31016)d4688df
[Fiber] Track Event Time, startTransition Time and setState Time (#31008)15da917
Don't read currentTransition back from internals (#30991)Sourced from react-dom's releases.
19.0.0 (December 5, 2024)
Below is a list of all new features, APIs, deprecations, and breaking changes. Read React 19 release post and React 19 upgrade guide for more information.
Note: To help make the upgrade to React 19 easier, we’ve published a react@18.3 release that is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19. We recommend upgrading to React 18.3.1 first to help identify any issues before upgrading to React 19.
New Features
React
- Actions:
startTransition
can now accept async functions. Functions passed tostartTransition
are called “Actions”. A given Transition can include one or more Actions which update state in the background and update the UI with one commit. In addition to updating state, Actions can now perform side effects including async requests, and the Action will wait for the work to finish before finishing the Transition. This feature allows Transitions to include side effects likefetch()
in the pending state, and provides support for error handling, and optimistic updates.useActionState
: is a new hook to order Actions inside of a Transition with access to the state of the action, and the pending state. It accepts a reducer that can call Actions, and the initial state used for first render. It also accepts an optional string that is used if the action is passed to a formaction
prop to support progressive enhancement in forms.useOptimistic
: is a new hook to update state while a Transition is in progress. It returns the state, and a set function that can be called inside a transition to “optimistically” update the state to expected final value immediately while the Transition completes in the background. When the transition finishes, the state is updated to the new value.use
: is a new API that allows reading resources in render. In React 19,use
accepts a promise or Context. If provided a promise,use
will suspend until a value is resolved.use
can only be used in render but can be called conditionally.ref
as a prop: Refs can now be used as props, removing the need forforwardRef
.- Suspense sibling pre-warming: When a component suspends, React will immediately commit the fallback of the nearest Suspense boundary, without waiting for the entire sibling tree to render. After the fallback commits, React will schedule another render for the suspended siblings to “pre-warm” lazy requests.
React DOM Client
<form> action
prop: Form Actions allow you to manage forms automatically and integrate withuseFormStatus
. When a<form> action
succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the newrequestFormReset
API.<button> and <input> formAction
prop: Actions can be passed to theformAction
prop to configure form submission behavior. This allows using different Actions depending on the input.useFormStatus
: is a new hook that provides the status of the parent<form> action
, as if the form was a Context provider. The hook returns the values:pending
,data
,method
, andaction
.- Support for Document Metadata: We’ve added support for rendering document metadata tags in components natively. React will automatically hoist them into the
<head>
section of the document.- Support for Stylesheets: React 19 will ensure stylesheets are inserted into the
<head>
on the client before revealing the content of a Suspense boundary that depends on that stylesheet.- Support for async scripts: Async scripts can be rendered anywhere in the component tree and React will handle ordering and deduplication.
- Support for preloading resources: React 19 ships with
preinit
,preload
,prefetchDNS
, andpreconnect
APIs to optimize initial page loads by moving discovery of additional resources like fonts out of stylesheet loading. They can also be used to prefetch resources used by an anticipated navigation.React DOM Server
- Added
prerender
andprerenderToNodeStream
APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. UnlikerenderToString
, they wait for data to load for HTML generation.React Server Components
- RSC features such as directives, server components, and server functions are now stable. This means libraries that ship with Server Components can now target React 19 as a peer dependency with a react-server export condition for use in frameworks that support the Full-stack React Architecture. The underlying APIs used to implement a React Server Components bundler or framework do not follow semver and may break between minors in React 19.x. See docs for how to support React Server Components.
Deprecations
- Deprecated:
element.ref
access: React 19 supports ref as a prop, so we’re deprecatingelement.ref
in favor ofelement.props.ref
. Accessing will result in a warning.react-test-renderer
: In React 19, react-test-renderer logs a deprecation warning and has switched to concurrent rendering for web usage. We recommend migrating your tests to@testinglibrary
.com/docs/react-testing-library/intro/) or@testingesting-library
.com/docs/react-native-testing-library/intro)Breaking Changes
React 19 brings in a number of breaking changes, including the removals of long-deprecated APIs. We recommend first upgrading to
18.3.1
, where we've added additional deprecation warnings. Check out the upgrade guide for more details and guidance on codemodding.React
- New JSX Transform is now required: We introduced a new JSX transform in 2020 to improve bundle size and use JSX without importing React. In React 19, we’re adding additional improvements like using ref as a prop and JSX speed improvements that require the new transform.
- Errors in render are not re-thrown: Errors that are not caught by an Error Boundary are now reported to window.reportError. Errors that are caught by an Error Boundary are reported to console.error. We’ve introduced
onUncaughtError
andonCaughtError
methods tocreateRoot
andhydrateRoot
to customize this error handling.- Removed:
propTypes
: UsingpropTypes
will now be silently ignored. If required, we recommend migrating to TypeScript or another type-checking solution.- Removed:
defaultProps
for functions: ES6 default parameters can be used in place. Class components continue to supportdefaultProps
since there is no ES6 alternative.- Removed:
contextTypes
andgetChildContext
: Legacy Context for class components has been removed in favor of thecontextType
API.
... (truncated)
Sourced from react-dom's changelog.
19.0.0 (December 5, 2024)
Below is a list of all new features, APIs, deprecations, and breaking changes. Read React 19 release post and React 19 upgrade guide for more information.
Note: To help make the upgrade to React 19 easier, we’ve published a react@18.3 release that is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19. We recommend upgrading to React 18.3.1 first to help identify any issues before upgrading to React 19.
New Features
React
- Actions:
startTransition
can now accept async functions. Functions passed tostartTransition
are called “Actions”. A given Transition can include one or more Actions which update state in the background and update the UI with one commit. In addition to updating state, Actions can now perform side effects including async requests, and the Action will wait for the work to finish before finishing the Transition. This feature allows Transitions to include side effects likefetch()
in the pending state, and provides support for error handling, and optimistic updates.useActionState
: is a new hook to order Actions inside of a Transition with access to the state of the action, and the pending state. It accepts a reducer that can call Actions, and the initial state used for first render. It also accepts an optional string that is used if the action is passed to a formaction
prop to support progressive enhancement in forms.useOptimistic
: is a new hook to update state while a Transition is in progress. It returns the state, and a set function that can be called inside a transition to “optimistically” update the state to expected final value immediately while the Transition completes in the background. When the transition finishes, the state is updated to the new value.use
: is a new API that allows reading resources in render. In React 19,use
accepts a promise or Context. If provided a promise,use
will suspend until a value is resolved.use
can only be used in render but can be called conditionally.ref
as a prop: Refs can now be used as props, removing the need forforwardRef
.- Suspense sibling pre-warming: When a component suspends, React will immediately commit the fallback of the nearest Suspense boundary, without waiting for the entire sibling tree to render. After the fallback commits, React will schedule another render for the suspended siblings to “pre-warm” lazy requests.
React DOM Client
<form> action
prop: Form Actions allow you to manage forms automatically and integrate withuseFormStatus
. When a<form> action
succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the newrequestFormReset
API.<button> and <input> formAction
prop: Actions can be passed to theformAction
prop to configure form submission behavior. This allows using different Actions depending on the input.useFormStatus
: is a new hook that provides the status of the parent<form> action
, as if the form was a Context provider. The hook returns the values:pending
,data
,method
, andaction
.- Support for Document Metadata: We’ve added support for rendering document metadata tags in components natively. React will automatically hoist them into the
<head>
section of the document.- Support for Stylesheets: React 19 will ensure stylesheets are inserted into the
<head>
on the client before revealing the content of a Suspense boundary that depends on that stylesheet.- Support for async scripts: Async scripts can be rendered anywhere in the component tree and React will handle ordering and deduplication.
- Support for preloading resources: React 19 ships with
preinit
,preload
,prefetchDNS
, andpreconnect
APIs to optimize initial page loads by moving discovery of additional resources like fonts out of stylesheet loading. They can also be used to prefetch resources used by an anticipated navigation.React DOM Server
- Added
prerender
andprerenderToNodeStream
APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. UnlikerenderToString
, they wait for data to load for HTML generation.React Server Components
- RSC features such as directives, server components, and server functions are now stable. This means libraries that ship with Server Components can now target React 19 as a peer dependency with a react-server export condition for use in frameworks that support the Full-stack React Architecture. The underlying APIs used to implement a React Server Components bundler or framework do not follow semver and may break between minors in React 19.x. See docs for how to support React Server Components.
Deprecations
- Deprecated:
element.ref
access: React 19 supports ref as a prop, so we’re deprecatingelement.ref
in favor ofelement.props.ref
. Accessing will result in a warning.react-test-renderer
: In React 19, react-test-renderer logs a deprecation warning and has switched to concurrent rendering for web usage. We recommend migrating your tests to@testing-library/react
or@testing-library/react-native
Breaking Changes
React 19 brings in a number of breaking changes, including the removals of long-deprecated APIs. We recommend first upgrading to
18.3.1
, where we've added additional deprecation warnings. Check out the upgrade guide for more details and guidance on codemodding.React
- New JSX Transform is now required: We introduced a new JSX transform in 2020 to improve bundle size and use JSX without importing React. In React 19, we’re adding additional improvements like using ref as a prop and JSX speed improvements that require the new transform.
- Errors in render are not re-thrown: Errors that are not caught by an Error Boundary are now reported to window.reportError. Errors that are caught by an Error Boundary are reported to console.error. We’ve introduced
onUncaughtError
andonCaughtError
methods tocreateRoot
andhydrateRoot
to customize this error handling.- Removed:
propTypes
: UsingpropTypes
will now be silently ignored. If required, we recommend migrating to TypeScript or another type-checking solution.- Removed:
defaultProps
for functions: ES6 default parameters can be used in place. Class components continue to supportdefaultProps
since there is no ES6 alternative.
... (truncated)
989af12
Make prerendering always non-blocking with fix (#31452)e137890
[string-refs] cleanup string ref code (#31443)07aa494
Remove enableRefAsProp feature flag (#30346)cae764c
Revert "[Re-land] Make prerendering always non-blocking (#31268)"
(#31355)d49123f
Expose prerender() for SSG in stable (#31298)6c4bbc7
[Re-land] Make prerendering always non-blocking (#31268)d8c90fa
Disable infinite render loop detection (#31088)67fee58
[Fizz] Start initial work immediately (#31079)76aee6f
Revert "Make prerendering always non-blocking" (#31080)0f1856c
Make prerendering always non-blocking (#31056)