Model Float on Hoistables semantics #26106
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sebmarkbage
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This feels like the right direction. We can nit pick later but let's get this in sooner rather than later because it'll be a pain to rebase later for everyone involved.
Fix the lints. Add a more comprehensive PR description to others and our future self what's going here, before landing.
| }, | ||
| }, | ||
| }; | ||
| export function compareResourcePropsForWarning( |
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This doesn't need to be exported.
You can leave the helper but I'm a little suspicious when I see code like this generic diffing. We don't really have that anywhere else and we do have a lot of diffing but we can never get away with it being this generic. We usually just do it inline.
One consideration here is if the props that materialize to the same thing are truly different. E.g. a number and a string of the same value. Is that different? Are there no special cases?
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yeah I already had to do some selective processing of the diff for some cases like if you don't pass a precedence in preinit that still is compatible with a "default" precedence on a stylesheet link. I'll see about refactoring it in a future update to be more direct
| )); | ||
| if (current === null) { | ||
| if (!getIsHydrating() && resource === null) { | ||
| // This is not a Resource Hoistable and we aren't hydrating so we construct the |
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construct the... what?
| @@ -494,6 +494,7 @@ describe('ReactDOMComponent', () => { | |||
| 'To fix this, either do not render the element at all ' + | |||
| 'or pass null to href instead of an empty string.', | |||
| ); | |||
| console.log('container', container.outerHTML); | |||
| internalInstanceHandle: Object, | ||
| ): Instance { | ||
| const ownerDocument = getDocumentFromRoot(hoistableRoot); | ||
| const nodes = ownerDocument.querySelectorAll(type); |
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getElementsByTagName by-passes the parsing.
| ); | ||
| childString = ''; | ||
| } | ||
| nodeLoop: for (let i = 0; i < nodes.length; i++) { |
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I'm not loving the computational complexity of N * N queries for number of nodes. I wonder if we need to do something like caching in a Map.
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yeah same, i'll think about more efficient implementations for a follow up
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## Hoistables In the original implementation of Float, all hoisted elements were treated like Resources. They had deduplication semantics and hydrated based on a key. This made certain kinds of hoists very challenging such as sequences of meta tags for `og:image:...` metadata. The reason is each tag along is not dedupable based on only it's intrinsic properties. two identical tags may need to be included and hoisted together with preceding meta tags that describe a semantic object with a linear set of html nodes. It was clear that the concept of Browser Resources (stylesheets / scripts / preloads) did not extend universally to all hositable tags (title, meta, other links, etc...) Additionally while Resources benefit from deduping they suffer an inability to update because while we may have multiple rendered elements that refer to a single Resource it isn't unambiguous which element owns the props on the underlying resource. We could try merging props, but that is still really hard to reason about for authors. Instead we restrict Resource semantics to freezing the props at the time the Resource is first constructed and warn if you attempt to render the same Resource with different props via another rendered element or by updating an existing element for that Resource. This lack of updating restriction is however way more extreme than necessary for instances that get hoisted but otherwise do not dedupe; where there is a well defined DOM instance for each rendered element. We should be able to update props on these instances. Hoistable is a generalization of what Float tries to model for hoisting. Instead of assuming every hoistable element is a Resource we now have two distinct categories, hoistable elements and hoistable resources. As one might guess the former has semantics that match regular Host Components except the placement of the node is usually in the <head>. The latter continues to behave how the original implementation of HostResource behaved with the first iteration of Float ### Hoistable Element On the server hoistable elements render just like regular tags except the output is stored in special queues that can be emitted in the stream earlier than they otherwise would be if rendered in place. This also allow for instance the ability to render a hoistable before even rendering the <html> tag because the queues for hoistable elements won't flush until after we have flushed the preamble (`<DOCTYPE html><html><head>`). On the client, hoistable elements largely operate like HostComponents. The most notable difference is in the hydration strategy. If we are hydrating and encounter a hoistable element we will look for all tags in the document that could potentially be a match and we check whether the attributes match the props for this particular instance. We also do this in the commit phase rather than the render phase. The reason hydration can be done for HostComponents in render is the instance will be removed from the document if hydration fails so mutating it in render is safe. For hoistables the nodes are not in a hydration boundary (Root or SuspenseBoundary at time of writing) and thus if hydration fails and we may have an instance marked as bound to some Fiber when that Fiber never commits. Moving the hydration matching to commit ensures we will always succeed in pairing the hoisted DOM instance with a Fiber that has committed. ### Hoistable Resource On the server and client the semantics of Resources are largely the same they just don't apply to title, meta, and most link tags anymore. Resources hoist and dedupe via an `href` key and are ref counted. In a future update we will add a garbage collector so we can clean up Resources that no longer have any references ## `<style>` support In earlier implementations there was no support for <style> tags. This PR adds support for treating `<style href="..." precedence="...">...</style>` as a Resource analagous to `<link rel="stylesheet" href="..." precedence="..." />` It may seem odd at first to require an href to get Resource semantics for a style tag. The rationale is that these are for inlining of actual external stylesheets as an optimization and for URI like scoping of inline styles for css-in-js libraries. The href indicates that the key space for `<style>` and `<link rel="stylesheet" />` Resources is shared. and the precedence is there to allow for interleaving of both kinds of Style resources. This is an advanced feature that we do not expect most app developers to use directly but will be quite handy for various styling libraries and for folks who want to inline as much as possible once Fizz supports this feature. ## refactor notes * HostResource Fiber type is renamed HostHoistable to reflect the generalization of the concept * The Resource object representation is modified to reduce hidden class checks and to use less memory overall * The thing that distinguishes a resource from an element is whether the Fiber has a memoizedState. If it does, it will use resource semantics, otherwise element semantics * The time complexity of matching hositable elements for hydration should be improved DiffTrain build for [6396b66](6396b66) [View git log for this commit](https://github.com/facebook/react/commits/6396b664118442f3c2eae7bf13732fcb27bda98f)
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| return root.ownerDocument || root; | ||
| } | ||
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| export function getHoistableRoot(container: Container): HoistableRoot { | ||
| // Flow thinks getRootNode returns Node but we know it is actualy either a Document or ShadowRoot | ||
| return ((container.getRootNode(): any): Document | ShadowRoot); |
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@gnoff should we be using the getRootNode helper from above here? This is throwing a bunch of errors in internal classic component tests
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I forgot to guard the `getRootNode` call in #26106 and it fails in IE8 and old jsdom. I consolidated the implementation a bit and removed the unguarded call
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I forgot to guard the `getRootNode` call in #26106 and it fails in IE8 and old jsdom. I consolidated the implementation a bit and removed the unguarded call DiffTrain build for [64acd39](64acd39) [View git log for this commit](https://github.com/facebook/react/commits/64acd3918a26d92773d3dd451a735603ef50d3a7)
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Wow. Some magic as usual :-P |
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Summary: This sync includes the following changes: - **[86c8c8db7](facebook/react@86c8c8db7 )**: test: Don't retry flushActWork if flushUntilNextPaint threw ([#26121](facebook/react#26121)) //<Sebastian Silbermann>// - **[64acd3918](facebook/react@64acd3918 )**: remove unguarded getRootNode call ([#26152](facebook/react#26152)) //<Josh Story>// - **[71cace4d3](facebook/react@71cace4d3 )**: Migrate testRunner from jasmine2 to jest-circus ([#26144](facebook/react#26144)) //<Ming Ye>// - **[c8510227c](facebook/react@c8510227c )**: Treat displayName as undefined ([#26148](facebook/react#26148)) //<Sebastian Markbåge>// - **[55542bc73](facebook/react@55542bc73 )**: Update jest printBasicPrototype config ([#26142](facebook/react#26142)) //<Ming Ye>// - **[6396b6641](facebook/react@6396b6641 )**: Model Float on Hoistables semantics ([#26106](facebook/react#26106)) //<Josh Story>// - **[ef9f6e77b](facebook/react@ef9f6e77b )**: Enable passing Server References from Server to Client ([#26124](facebook/react#26124)) //<Sebastian Markbåge>// - **[35698311d](facebook/react@35698311d )**: Update jest escapeString config ([#26140](facebook/react#26140)) //<Ming Ye>// - **[6ddcbd4f9](facebook/react@6ddcbd4f9 )**: [flow] enable LTI inference mode ([#26104](facebook/react#26104)) //<Jan Kassens>// - **[53b1f69ba](facebook/react@53b1f69ba )**: Implement unstable_getBoundingClientRect in RN Fabric refs ([#26137](facebook/react#26137)) //<Rubén Norte>// - **[594093496](facebook/react@594093496 )**: Update to Jest 29 ([#26088](facebook/react#26088)) //<Ming Ye>// - **[28fcae062](facebook/react@28fcae062 )**: Add support for SVG `transformOrigin` prop ([#26130](facebook/react#26130)) //<Aravind D>// - **[3ff1540e9](facebook/react@3ff1540e9 )**: Prefer JSX in ReactNoop assertions (to combat out-of-memory test runs) ([#26127](facebook/react#26127)) //<Sebastian Silbermann>// - **[01a0c4e12](facebook/react@01a0c4e12 )**: Add Edge Server Builds for workerd / edge-light ([#26116](facebook/react#26116)) //<Sebastian Markbåge>// - **[f0cf832e1](facebook/react@f0cf832e1 )**: Update Flight Fixture to "use client" instead of .client.js ([#26118](facebook/react#26118)) //<Sebastian Markbåge>// - **[03a216070](facebook/react@03a216070 )**: Rename "dom" fork to "dom-node" and "bun" fork to "dom-bun" ([#26117](facebook/react#26117)) //<Sebastian Markbåge>// - **[4bf2113a1](facebook/react@4bf2113a1 )**: Revert "Move the Webpack manifest config to one level deeper ([#26083](facebook/react#26083))" ([#26111](facebook/react#26111)) //<Sebastian Markbåge>// - **[2ef24145e](facebook/react@2ef24145e )**: [flow] upgrade to 0.199.0 ([#26096](facebook/react#26096)) //<Jan Kassens>// - **[922dd7ba5](facebook/react@922dd7ba5 )**: Revert the outer module object to an object ([#26093](facebook/react#26093)) //<Sebastian Markbåge>// - **[9d111ffdf](facebook/react@9d111ffdf )**: Serialize Promises through Flight ([#26086](facebook/react#26086)) //<Sebastian Markbåge>// - **[0ba4698c7](facebook/react@0ba4698c7 )**: Fix async test in React reconciler ([#26087](facebook/react#26087)) //<Ming Ye>// - **[8c234c0de](facebook/react@8c234c0de )**: Move the Webpack manifest config to one level deeper ([#26083](facebook/react#26083)) //<Sebastian Markbåge>// - **[977bccd24](facebook/react@977bccd24 )**: Refactor Flight Encoding ([#26082](facebook/react#26082)) //<Sebastian Markbåge>// - **[d7bb524ad](facebook/react@d7bb524ad )**: [cleanup] Remove unused package jest-mock-scheduler ([#26084](facebook/react#26084)) //<Ming Ye>// - **[6b3083266](facebook/react@6b3083266 )**: Upgrade prettier ([#26081](facebook/react#26081)) //<Jan Kassens>// - **[1f5ce59dd](facebook/react@1f5ce59dd )**: [cleanup] fully roll out warnAboutSpreadingKeyToJSX ([#26080](facebook/react#26080)) //<Jan Kassens>// Changelog: [General][Changed] - React Native sync for revisions 48b687f...fccf3a9 jest_e2e[run_all_tests] Reviewed By: rubennorte Differential Revision: D43305607 fbshipit-source-id: 8da7567ca2a182f4be27788935c2da30a731f83b
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Summary: This sync includes the following changes: - **[86c8c8db7](facebook/react@86c8c8db7 )**: test: Don't retry flushActWork if flushUntilNextPaint threw ([facebook#26121](facebook/react#26121)) //<Sebastian Silbermann>// - **[64acd3918](facebook/react@64acd3918 )**: remove unguarded getRootNode call ([facebook#26152](facebook/react#26152)) //<Josh Story>// - **[71cace4d3](facebook/react@71cace4d3 )**: Migrate testRunner from jasmine2 to jest-circus ([facebook#26144](facebook/react#26144)) //<Ming Ye>// - **[c8510227c](facebook/react@c8510227c )**: Treat displayName as undefined ([facebook#26148](facebook/react#26148)) //<Sebastian Markbåge>// - **[55542bc73](facebook/react@55542bc73 )**: Update jest printBasicPrototype config ([facebook#26142](facebook/react#26142)) //<Ming Ye>// - **[6396b6641](facebook/react@6396b6641 )**: Model Float on Hoistables semantics ([facebook#26106](facebook/react#26106)) //<Josh Story>// - **[ef9f6e77b](facebook/react@ef9f6e77b )**: Enable passing Server References from Server to Client ([facebook#26124](facebook/react#26124)) //<Sebastian Markbåge>// - **[35698311d](facebook/react@35698311d )**: Update jest escapeString config ([facebook#26140](facebook/react#26140)) //<Ming Ye>// - **[6ddcbd4f9](facebook/react@6ddcbd4f9 )**: [flow] enable LTI inference mode ([facebook#26104](facebook/react#26104)) //<Jan Kassens>// - **[53b1f69ba](facebook/react@53b1f69ba )**: Implement unstable_getBoundingClientRect in RN Fabric refs ([facebook#26137](facebook/react#26137)) //<Rubén Norte>// - **[594093496](facebook/react@594093496 )**: Update to Jest 29 ([facebook#26088](facebook/react#26088)) //<Ming Ye>// - **[28fcae062](facebook/react@28fcae062 )**: Add support for SVG `transformOrigin` prop ([facebook#26130](facebook/react#26130)) //<Aravind D>// - **[3ff1540e9](facebook/react@3ff1540e9 )**: Prefer JSX in ReactNoop assertions (to combat out-of-memory test runs) ([facebook#26127](facebook/react#26127)) //<Sebastian Silbermann>// - **[01a0c4e12](facebook/react@01a0c4e12 )**: Add Edge Server Builds for workerd / edge-light ([facebook#26116](facebook/react#26116)) //<Sebastian Markbåge>// - **[f0cf832e1](facebook/react@f0cf832e1 )**: Update Flight Fixture to "use client" instead of .client.js ([facebook#26118](facebook/react#26118)) //<Sebastian Markbåge>// - **[03a216070](facebook/react@03a216070 )**: Rename "dom" fork to "dom-node" and "bun" fork to "dom-bun" ([facebook#26117](facebook/react#26117)) //<Sebastian Markbåge>// - **[4bf2113a1](facebook/react@4bf2113a1 )**: Revert "Move the Webpack manifest config to one level deeper ([facebook#26083](facebook/react#26083))" ([facebook#26111](facebook/react#26111)) //<Sebastian Markbåge>// - **[2ef24145e](facebook/react@2ef24145e )**: [flow] upgrade to 0.199.0 ([facebook#26096](facebook/react#26096)) //<Jan Kassens>// - **[922dd7ba5](facebook/react@922dd7ba5 )**: Revert the outer module object to an object ([facebook#26093](facebook/react#26093)) //<Sebastian Markbåge>// - **[9d111ffdf](facebook/react@9d111ffdf )**: Serialize Promises through Flight ([facebook#26086](facebook/react#26086)) //<Sebastian Markbåge>// - **[0ba4698c7](facebook/react@0ba4698c7 )**: Fix async test in React reconciler ([facebook#26087](facebook/react#26087)) //<Ming Ye>// - **[8c234c0de](facebook/react@8c234c0de )**: Move the Webpack manifest config to one level deeper ([facebook#26083](facebook/react#26083)) //<Sebastian Markbåge>// - **[977bccd24](facebook/react@977bccd24 )**: Refactor Flight Encoding ([facebook#26082](facebook/react#26082)) //<Sebastian Markbåge>// - **[d7bb524ad](facebook/react@d7bb524ad )**: [cleanup] Remove unused package jest-mock-scheduler ([facebook#26084](facebook/react#26084)) //<Ming Ye>// - **[6b3083266](facebook/react@6b3083266 )**: Upgrade prettier ([facebook#26081](facebook/react#26081)) //<Jan Kassens>// - **[1f5ce59dd](facebook/react@1f5ce59dd )**: [cleanup] fully roll out warnAboutSpreadingKeyToJSX ([facebook#26080](facebook/react#26080)) //<Jan Kassens>// Changelog: [General][Changed] - React Native sync for revisions 48b687f...fccf3a9 jest_e2e[run_all_tests] Reviewed By: rubennorte Differential Revision: D43305607 fbshipit-source-id: 8da7567ca2a182f4be27788935c2da30a731f83b
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This PR contains the following updates: | Package | Type | Update | Change | |---|---|---|---| | [@types/react](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/react) ([source](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react)) | devDependencies | major | [`18.3.18` -> `19.0.7`](https://renovatebot.com/diffs/npm/@types%2freact/18.3.18/19.0.7) | | [@types/react-dom](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/react-dom) ([source](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react-dom)) | devDependencies | major | [`18.3.5` -> `19.0.3`](https://renovatebot.com/diffs/npm/@types%2freact-dom/18.3.5/19.0.3) | | [react](https://react.dev/) ([source](https://github.com/facebook/react/tree/HEAD/packages/react)) | dependencies | major | [`18.3.1` -> `19.0.0`](https://renovatebot.com/diffs/npm/react/18.3.1/19.0.0) | | [react-dom](https://react.dev/) ([source](https://github.com/facebook/react/tree/HEAD/packages/react-dom)) | dependencies | major | [`18.3.1` -> `19.0.0`](https://renovatebot.com/diffs/npm/react-dom/18.3.1/19.0.0) | --- ### Release Notes <details> <summary>facebook/react (react)</summary> ### [`v19.0.0`](https://github.com/facebook/react/blob/HEAD/CHANGELOG.md#1900-December-5-2024) [Compare Source](https://github.com/facebook/react/compare/v18.3.1...v19.0.0) Below is a list of all new features, APIs, deprecations, and breaking changes. Read [React 19 release post](https://react.dev/blog/2024/04/25/react-19) and [React 19 upgrade guide](https://react.dev/blog/2024/04/25/react-19-upgrade-guide) for more information. > Note: To help make the upgrade to React 19 easier, we’ve published a [email protected] 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 to `startTransition` 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 like `fetch()` 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 form `action` 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 for `forwardRef`. - **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 with `useFormStatus`. When a `<form> action` succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the new `requestFormReset` API. - `<button> and <input> formAction` prop: Actions can be passed to the `formAction` 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`, and `action`. - 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`, and `preconnect` 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` and `prerenderToNodeStream` APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. Unlike `renderToString`, 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](https://19.react.dev/reference/rsc/server-components) for how to support React Server Components. ##### Deprecations - Deprecated: `element.ref` access: React 19 supports ref as a prop, so we’re deprecating `element.ref` in favor of `element.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](https://testing-library.com/docs/react-testing-library/intro/) or [@​testing-library/react-native](https://testing-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](https://19.react.dev/blog/2024/04/25/react-19-upgrade-guide) for more details and guidance on codemodding. ##### React - New JSX Transform is now required: We introduced [a new JSX transform](https://legacy.reactjs.org/blog/2020/09/22/introducing-the-new-jsx-transform.html) 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` and `onCaughtError` methods to `createRoot` and `hydrateRoot` to customize this error handling. - Removed: `propTypes`: Using `propTypes` 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 support `defaultProps` since there is no ES6 alternative. - Removed: `contextTypes` and `getChildContext`: Legacy Context for class components has been removed in favor of the `contextType` API. - Removed: string refs: Any usage of string refs need to be migrated to ref callbacks. - Removed: Module pattern factories: A rarely used pattern that can be migrated to regular functions. - Removed: `React.createFactory`: Now that JSX is broadly supported, all `createFactory` usage can be migrated to JSX components. - Removed: `react-test-renderer/shallow`: This has been a re-export of [react-shallow-renderer](https://github.com/enzymejs/react-shallow-renderer) since React 18. If needed, you can continue to use the third-party package directly. We recommend using [@​testing-library/react](https://testing-library.com/docs/react-testing-library/intro/) or [@​testing-library/react-native](https://testing-library.com/docs/react-native-testing-library/intro) instead. ##### React DOM - Removed: `react-dom/test-utils`: We’ve moved `act` from `react-dom/test-utils` to react. All other utilities have been removed. - Removed: `ReactDOM`.`render`, `ReactDOM`.`hydrate`: These have been removed in favor of the concurrent equivalents: `ReactDOM`.`createRoot` and `ReactDOM.hydrateRoot`. - Removed: `unmountComponentAtNode`: Removed in favor of `root.unmount()`. - Removed: `ReactDOM`.`findDOMNode`: You can replace `ReactDOM`.`findDOMNode` with DOM Refs. ##### Notable Changes ##### React - `<Context>` as a provider: You can now render `<Context>` as a provider instead of `<Context.Provider>`. - Cleanup functions for refs: When the component unmounts, React will call the cleanup function returned from the ref callback. - `useDeferredValue` initial value argument: When provided, `useDeferredValue` will return the initial value for the initial render of a component, then schedule a re-render in the background with the `deferredValue` returned. - Support for Custom Elements: React 19 now passes all tests on [Custom Elements Everywhere](https://custom-elements-everywhere.com/). - StrictMode changes: `useMemo` and `useCallback` will now reuse the memoized results from the first render, during the second render. Additionally, StrictMode will now double-invoke ref callback functions on initial mount. - UMD builds removed: To load React 19 with a script tag, we recommend using an ESM-based CDN such as [esm.sh](http://esm.sh). ##### React DOM - Diffs for hydration errors: In the case of a mismatch, React 19 logs a single error with a diff of the mismatched content. - Compatibility with third-party scripts and extensions: React will now force a client re-render to fix up any mismatched content caused by elements inserted by third-party JS. ##### TypeScript Changes The most common changes can be codemodded with `npx types-react-codemod@latest preset-19 ./path-to-your-react-ts-files`. - Removed deprecated TypeScript types: - `ReactChild` (replacement: `React.ReactElement | number | string)` - `ReactFragment` (replacement: `Iterable<React.ReactNode>`) - `ReactNodeArray` (replacement: `ReadonlyArray<React.ReactNode>`) - `ReactText` (replacement: `number | string`) - `VoidFunctionComponent` (replacement: `FunctionComponent`) - `VFC` (replacement: `FC`) - Moved to `prop-types`: `Requireable`, `ValidationMap`, `Validator`, `WeakValidationMap` - Moved to `create-react-class`: `ClassicComponentClass`, `ClassicComponent`, `ClassicElement`, `ComponentSpec`, `Mixin`, `ReactChildren`, `ReactHTML`, `ReactSVG`, `SFCFactory` - Disallow implicit return in refs: refs can now accept cleanup functions. When you return something else, we can’t tell if you intentionally returned something not meant to clean up or returned the wrong value. Implicit returns of anything but functions will now error. - Require initial argument to `useRef`: The initial argument is now required to match `useState`, `createContext` etc - Refs are mutable by default: Ref objects returned from `useRef()` are now always mutable instead of sometimes being immutable. This feature was too confusing for users and conflicted with legit cases where refs were managed by React and manually written to. - Strict `ReactElement` typing: The props of React elements now default to `unknown` instead of `any` if the element is typed as `ReactElement` - JSX namespace in TypeScript: The global `JSX` namespace is removed to improve interoperability with other libraries using JSX. Instead, the JSX namespace is available from the React package: `import { JSX } from 'react'` - Better `useReducer` typings: Most `useReducer` usage should not require explicit type arguments.\ For example, ```diff -useReducer<React.Reducer<State, Action>>(reducer) +useReducer(reducer) ``` or ```diff -useReducer<React.Reducer<State, Action>>(reducer) +useReducer<State, Action>(reducer) ``` ##### All Changes ##### React - Add support for async Actions ([#​26621](https://github.com/facebook/react/pull/26621), [#​26726](https://github.com/facebook/react/pull/26726), [#​28078](https://github.com/facebook/react/pull/28078), [#​28097](https://github.com/facebook/react/pull/28097), [#​29226](https://github.com/facebook/react/pull/29226), [#​29618](https://github.com/facebook/react/pull/29618), [#​29670](https://github.com/facebook/react/pull/29670), [#​26716](https://github.com/facebook/react/pull/26716) by [@​acdlite](https://github.com/acdlite) and [@​sebmarkbage](https://github.com/sebmarkbage)) - Add `useActionState()` hook to update state based on the result of a Form Action ([#​27270](https://github.com/facebook/react/pull/27270), [#​27278](https://github.com/facebook/react/pull/27278), [#​27309](https://github.com/facebook/react/pull/27309), [#​27302](https://github.com/facebook/react/pull/27302), [#​27307](https://github.com/facebook/react/pull/27307), [#​27366](https://github.com/facebook/react/pull/27366), [#​27370](https://github.com/facebook/react/pull/27370), [#​27321](https://github.com/facebook/react/pull/27321), [#​27374](https://github.com/facebook/react/pull/27374), [#​27372](https://github.com/facebook/react/pull/27372), [#​27397](https://github.com/facebook/react/pull/27397), [#​27399](https://github.com/facebook/react/pull/27399), [#​27460](https://github.com/facebook/react/pull/27460), [#​28557](https://github.com/facebook/react/pull/28557), [#​27570](https://github.com/facebook/react/pull/27570), [#​27571](https://github.com/facebook/react/pull/27571), [#​28631](https://github.com/facebook/react/pull/28631), [#​28788](https://github.com/facebook/react/pull/28788), [#​29694](https://github.com/facebook/react/pull/29694), [#​29695](https://github.com/facebook/react/pull/29695), [#​29694](https://github.com/facebook/react/pull/29694), [#​29665](https://github.com/facebook/react/pull/29665), [#​28232](https://github.com/facebook/react/pull/28232), [#​28319](https://github.com/facebook/react/pull/28319) by [@​acdlite](https://github.com/acdlite), [@​eps1lon](https://github.com/eps1lon), and [@​rickhanlonii](https://github.com/rickhanlonii)) - Add `use()` API to read resources in render ([#​25084](https://github.com/facebook/react/pull/25084), [#​25202](https://github.com/facebook/react/pull/25202), [#​25207](https://github.com/facebook/react/pull/25207), [#​25214](https://github.com/facebook/react/pull/25214), [#​25226](https://github.com/facebook/react/pull/25226), [#​25247](https://github.com/facebook/react/pull/25247), [#​25539](https://github.com/facebook/react/pull/25539), [#​25538](https://github.com/facebook/react/pull/25538), [#​25537](https://github.com/facebook/react/pull/25537), [#​25543](https://github.com/facebook/react/pull/25543), [#​25561](https://github.com/facebook/react/pull/25561), [#​25620](https://github.com/facebook/react/pull/25620), [#​25615](https://github.com/facebook/react/pull/25615), [#​25922](https://github.com/facebook/react/pull/25922), [#​25641](https://github.com/facebook/react/pull/25641), [#​25634](https://github.com/facebook/react/pull/25634), [#​26232](https://github.com/facebook/react/pull/26232), [#​26536](https://github.com/facebook/react/pull/26535), [#​26739](https://github.com/facebook/react/pull/26739), [#​28233](https://github.com/facebook/react/pull/28233) by [@​acdlite](https://github.com/acdlite), [@​MofeiZ](https://github.com/mofeiZ), [@​sebmarkbage](https://github.com/sebmarkbage), [@​sophiebits](https://github.com/sophiebits), [@​eps1lon](https://github.com/eps1lon), and [@​hansottowirtz](https://github.com/hansottowirtz)) - Add `useOptimistic()` hook to display mutated state optimistically during an async mutation ([#​26740](https://github.com/facebook/react/pull/26740), [#​26772](https://github.com/facebook/react/pull/26772), [#​27277](https://github.com/facebook/react/pull/27277), [#​27453](https://github.com/facebook/react/pull/27453), [#​27454](https://github.com/facebook/react/pull/27454), [#​27936](https://github.com/facebook/react/pull/27936) by [@​acdlite](https://github.com/acdlite)) - Added an `initialValue` argument to `useDeferredValue()` hook ([#​27500](https://github.com/facebook/react/pull/27500), [#​27509](https://github.com/facebook/react/pull/27509), [#​27512](https://github.com/facebook/react/pull/27512), [#​27888](https://github.com/facebook/react/pull/27888), [#​27550](https://github.com/facebook/react/pull/27550) by [@​acdlite](https://github.com/acdlite)) - Support refs as props, warn on `element.ref` access ([#​28348](https://github.com/facebook/react/pull/28348), [#​28464](https://github.com/facebook/react/pull/28464), [#​28731](https://github.com/facebook/react/pull/28731) by [@​acdlite](https://github.com/acdlite)) - Support Custom Elements ([#​22184](https://github.com/facebook/react/pull/22184), [#​26524](https://github.com/facebook/react/pull/26524), [#​26523](https://github.com/facebook/react/pull/26523), [#​27511](https://github.com/facebook/react/pull/27511), [#​24541](https://github.com/facebook/react/pull/24541) by [@​josepharhar](https://github.com/josepharhar), [@​sebmarkbage](https://github.com/sebmarkbage), [@​gnoff](https://github.com/gnoff) and [@​eps1lon](https://github.com/eps1lon)) - Add ref cleanup function ([#​25686](https://github.com/facebook/react/pull/25686), [#​28883](https://github.com/facebook/react/pull/28883), [#​28910](https://github.com/facebook/react/pull/28910) by [@​sammy-SC](https://github.com/sammy-SC), [@​jackpope](https://github.com/jackpope), and [@​kassens](https://github.com/kassens)) - Sibling pre-rendering replaced by sibling pre-warming ([#​26380](https://github.com/facebook/react/pull/26380), [#​26549](https://github.com/facebook/react/pull/26549), [#​30761](https://github.com/facebook/react/pull/30761), [#​30800](https://github.com/facebook/react/pull/30800), [#​30762](https://github.com/facebook/react/pull/30762), [#​30879](https://github.com/facebook/react/pull/30879), [#​30934](https://github.com/facebook/react/pull/30934), [#​30952](https://github.com/facebook/react/pull/30952), [#​31056](https://github.com/facebook/react/pull/31056), [#​31452](https://github.com/facebook/react/pull/31452) by [@​sammy-SC](https://github.com/sammy-SC), [@​acdlite](https://github.com/acdlite), [@​gnoff](https://github.com/gnoff), [@​jackpope](https://github.com/jackpope), [@​rickhanlonii](https://github.com/rickhanlonii)) - Don’t rethrow errors at the root ([#​28627](https://github.com/facebook/react/pull/28627), [#​28641](https://github.com/facebook/react/pull/28641) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Batch sync discrete, continuous, and default lanes ([#​25700](https://github.com/facebook/react/pull/25700) by [@​tyao1](https://github.com/tyao1)) - Switch `<Context>` to mean `<Context.Provider>` ([#​28226](https://github.com/facebook/react/pull/28226) by [@​gaearon](https://github.com/gaearon)) - Changes to *StrictMode* - Handle `info`, `group`, and `groupCollapsed` in *StrictMode* logging ([#​25172](https://github.com/facebook/react/pull/25172) by [@​timneutkens](https://github.com/timneutkens)) - Refs are now attached/detached/attached in *StrictMode* ([#​25049](https://github.com/facebook/react/pull/25049) by [@​sammy-SC](https://github.com/sammy-SC)) - Fix `useSyncExternalStore()` hydration in *StrictMode* ([#​26791](https://github.com/facebook/react/pull/26791) by [@​sophiebits](https://github.com/sophiebits)) - Always trigger `componentWillUnmount()` in *StrictMode* ([#​26842](https://github.com/facebook/react/pull/26842) by [@​tyao1](https://github.com/tyao1)) - Restore double invoking `useState()` and `useReducer()` initializer functions in *StrictMode* ([#​28248](https://github.com/facebook/react/pull/28248) by [@​eps1lon](https://github.com/eps1lon)) - Reuse memoized result from first pass ([#​25583](https://github.com/facebook/react/pull/25583) by [@​acdlite](https://github.com/acdlite)) - Fix `useId()` in *StrictMode* ([#​25713](https://github.com/facebook/react/pull/25713) by [@​gnoff](https://github.com/gnoff)) - Add component name to *StrictMode* error messages ([#​25718](https://github.com/facebook/react/pull/25718) by [@​sammy-SC](https://github.com/sammy-SC)) - Add support for rendering BigInt ([#​24580](https://github.com/facebook/react/pull/24580) by [@​eps1lon](https://github.com/eps1lon)) - `act()` no longer checks `shouldYield` which can be inaccurate in test environments ([#​26317](https://github.com/facebook/react/pull/26317) by [@​acdlite](https://github.com/acdlite)) - Warn when keys are spread with props ([#​25697](https://github.com/facebook/react/pull/25697), [#​26080](https://github.com/facebook/react/pull/26080) by [@​sebmarkbage](https://github.com/sebmarkbage) and [@​kassens](https://github.com/kassens)) - Generate sourcemaps for production build artifacts ([#​26446](https://github.com/facebook/react/pull/26446) by [@​markerikson](https://github.com/markerikson)) - Improve stack diffing algorithm ([#​27132](https://github.com/facebook/react/pull/27132) by [@​KarimP](https://github.com/KarimP)) - Suspense throttling lowered from 500ms to 300ms ([#​26803](https://github.com/facebook/react/pull/26803) by [@​acdlite](https://github.com/acdlite)) - Lazily propagate context changes ([#​20890](https://github.com/facebook/react/pull/20890) by [@​acdlite](https://github.com/acdlite) and [@​gnoff](https://github.com/gnoff)) - Immediately rerender pinged fiber ([#​25074](https://github.com/facebook/react/pull/25074) by [@​acdlite](https://github.com/acdlite)) - Move update scheduling to microtask ([#​26512](https://github.com/facebook/react/pull/26512) by [@​acdlite](https://github.com/acdlite)) - Consistently apply throttled retries ([#​26611](https://github.com/facebook/react/pull/26611), [#​26802](https://github.com/facebook/react/pull/26802) by [@​acdlite](https://github.com/acdlite)) - Suspend Thenable/Lazy if it's used in React.Children ([#​28284](https://github.com/facebook/react/pull/28284) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Detect infinite update loops caused by render phase updates ([#​26625](https://github.com/facebook/react/pull/26625) by [@​acdlite](https://github.com/acdlite)) - Update conditional hooks warning ([#​29626](https://github.com/facebook/react/pull/29626) by [@​sophiebits](https://github.com/sophiebits)) - Update error URLs to go to new docs ([#​27240](https://github.com/facebook/react/pull/27240) by [@​rickhanlonii](https://github.com/rickhanlonii)) - Rename the `react.element` symbol to `react.transitional.element` ([#​28813](https://github.com/facebook/react/pull/28813) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Fix crash when suspending in shell during `useSyncExternalStore()` re-render ([#​27199](https://github.com/facebook/react/pull/27199) by [@​acdlite](https://github.com/acdlite)) - Fix incorrect “detected multiple renderers" error in tests ([#​22797](https://github.com/facebook/react/pull/22797) by [@​eps1lon](https://github.com/eps1lon)) - Fix bug where effect cleanup may be called twice after bailout ([#​26561](https://github.com/facebook/react/pull/26561) by [@​acdlite](https://github.com/acdlite)) - Fix suspending in shell during discrete update ([#​25495](https://github.com/facebook/react/pull/25495) by [@​acdlite](https://github.com/acdlite)) - Fix memory leak after repeated setState bailouts ([#​25309](https://github.com/facebook/react/pull/25309) by [@​acdlite](https://github.com/acdlite)) - Fix `useSyncExternalStore()` dropped update when state is dispatched in render phase ([#​25578](https://github.com/facebook/react/pull/25578) by [@​pandaiolo](https://github.com/pandaiolo)) - Fix logging when rendering a lazy fragment ([#​30372](https://github.com/facebook/react/pull/30372) by [@​tom-sherman](https://github.com/tom-sherman)) - Remove string refs ([#​25383](https://github.com/facebook/react/pull/25383), [#​28322](https://github.com/facebook/react/pull/28322) by [@​eps1lon](https://github.com/eps1lon) and [@​acdlite](https://github.com/acdlite)) - Remove Legacy Context ([#​30319](https://github.com/facebook/react/issues/30319) by [@​kassens](https://github.com/kassens)) - Remove `RefreshRuntime.findAffectedHostInstances` ([#​30538](https://github.com/facebook/react/pull/30538) by [@​gaearon](https://github.com/gaearon)) - Remove client caching from `cache()` API ([#​27977](https://github.com/facebook/react/pull/27977), [#​28250](https://github.com/facebook/react/pull/28250) by [@​acdlite](https://github.com/acdlite) and [@​gnoff](https://github.com/gnoff)) - Remove `propTypes` ([#​28324](https://github.com/facebook/react/pull/28324), [#​28326](https://github.com/facebook/react/pull/28326) by [@​gaearon](https://github.com/gaearon)) - Remove `defaultProps` support, except for classes ([#​28733](https://github.com/facebook/react/pull/28733) by [@​acdlite](https://github.com/acdlite)) - Remove UMD builds ([#​28735](https://github.com/facebook/react/pull/28735) by [@​gnoff](https://github.com/gnoff)) - Remove delay for non-transition updates ([#​26597](https://github.com/facebook/react/pull/26597) by [@​acdlite](https://github.com/acdlite)) - Remove `createFactory` ([#​27798](https://github.com/facebook/react/pull/27798) by [@​kassens](https://github.com/kassens)) ##### React DOM - Adds Form Actions to handle form submission ([#​26379](https://github.com/facebook/react/pull/26379), [#​26674](https://github.com/facebook/react/pull/26674), [#​26689](https://github.com/facebook/react/pull/26689), [#​26708](https://github.com/facebook/react/pull/26708), [#​26714](https://github.com/facebook/react/pull/26714), [#​26735](https://github.com/facebook/react/pull/26735), [#​26846](https://github.com/facebook/react/pull/26846), [#​27358](https://github.com/facebook/react/pull/27358), [#​28056](https://github.com/facebook/react/pull/28056) by [@​sebmarkbage](https://github.com/sebmarkbage), [@​acdlite](https://github.com/acdlite), and [@​jupapios](https://github.com/jupapios)) - Add `useFormStatus()` hook to provide status information of the last form submission ([#​26719](https://github.com/facebook/react/pull/26719), [#​26722](https://github.com/facebook/react/pull/26722), [#​26788](https://github.com/facebook/react/pull/26788), [#​29019](https://github.com/facebook/react/pull/29019), [#​28728](https://github.com/facebook/react/pull/28728), [#​28413](https://github.com/facebook/react/pull/28413) by [@​acdlite](https://github.com/acdlite) and [@​eps1lon](https://github.com/eps1lon)) - Support for Document Metadata. Adds `preinit`, `preinitModule`, `preconnect`, `prefetchDNS`, `preload`, and `preloadModule` APIs. - [#​25060](https://github.com/facebook/react/pull/25060), [#​25243](https://github.com/facebook/react/pull/25243), [#​25388](https://github.com/facebook/react/pull/25388), [#​25432](https://github.com/facebook/react/pull/25432), [#​25436](https://github.com/facebook/react/pull/25436), [#​25426](https://github.com/facebook/react/pull/25426), [#​25500](https://github.com/facebook/react/pull/25500), [#​25480](https://github.com/facebook/react/pull/25480), [#​25508](https://github.com/facebook/react/pull/25508), [#​25515](https://github.com/facebook/react/pull/25515), [#​25514](https://github.com/facebook/react/pull/25514), [#​25532](https://github.com/facebook/react/pull/25532), [#​25536](https://github.com/facebook/react/pull/25536), [#​25534](https://github.com/facebook/react/pull/25534), [#​25546](https://github.com/facebook/react/pull/25546), [#​25559](https://github.com/facebook/react/pull/25559), [#​25569](https://github.com/facebook/react/pull/25569), [#​25599](https://github.com/facebook/react/pull/25599), [#​25689](https://github.com/facebook/react/pull/25689), [#​26106](https://github.com/facebook/react/pull/26106), [#​26152](https://github.com/facebook/react/pull/26152), [#​26239](https://github.com/facebook/react/pull/26239), [#​26237](https://github.com/facebook/react/pull/26237), [#​26280](https://github.com/facebook/react/pull/26280), [#​26154](https://github.com/facebook/react/pull/26154), [#​26256](https://github.com/facebook/react/pull/26256), [#​26353](https://github.com/facebook/react/pull/26353), [#​26427](https://github.com/facebook/react/pull/26427), [#​26450](https://github.com/facebook/react/pull/26450), [#​26502](https://github.com/facebook/react/pull/26502), [#​26514](https://github.com/facebook/react/pull/26514), [#​26531](https://github.com/facebook/react/pull/26531), [#​26532](https://github.com/facebook/react/pull/26532), [#​26557](https://github.com/facebook/react/pull/26557), [#​26871](https://github.com/facebook/react/pull/26871), [#​26881](https://github.com/facebook/react/pull/26881), [#​26877](https://github.com/facebook/react/pull/26877), [#​26873](https://github.com/facebook/react/pull/26873), [#​26880](https://github.com/facebook/react/pull/26880), [#​26942](https://github.com/facebook/react/pull/26942), [#​26938](https://github.com/facebook/react/pull/26938), [#​26940](https://github.com/facebook/react/pull/26940), [#​26939](https://github.com/facebook/react/pull/26939), [#​27030](https://github.com/facebook/react/pull/27030), [#​27201](https://github.com/facebook/react/pull/27201), [#​27212](https://github.com/facebook/react/pull/27212), [#​27217](https://github.com/facebook/react/pull/27217), [#​27218](https://github.com/facebook/react/pull/27218), [#​27220](https://github.com/facebook/react/pull/27220), [#​27224](https://github.com/facebook/react/pull/27224), [#​27223](https://github.com/facebook/react/pull/27223), [#​27269](https://github.com/facebook/react/pull/27269), [#​27260](https://github.com/facebook/react/pull/27260), [#​27347](https://github.com/facebook/react/pull/27347), [#​27346](https://github.com/facebook/react/pull/27346), [#​27361](https://github.com/facebook/react/pull/27361), [#​27400](https://github.com/facebook/react/pull/27400), [#​27541](https://github.com/facebook/react/pull/27541), [#​27610](https://github.com/facebook/react/pull/27610), [#​28110](https://github.com/facebook/react/pull/28110), [#​29693](https://github.com/facebook/react/pull/29693), [#​29732](https://github.com/facebook/react/pull/29732), [#​29811](https://github.com/facebook/react/pull/29811), [#​27586](https://github.com/facebook/react/pull/27586), [#​28069](https://github.com/facebook/react/pull/28069) by [@​gnoff](https://github.com/gnoff), [@​sebmarkbage](https://github.com/sebmarkbage), [@​acdlite](https://github.com/acdlite), [@​kassens](https://github.com/kassens), [@​sokra](https://github.com/sokra), [@​sweetliquid](https://github.com/sweetliquid) - Add `fetchPriority` to `<img>` and `<link>` ([#​25927](https://github.com/facebook/react/pull/25927) by [@​styfle](https://github.com/styfle)) - Add support for SVG `transformOrigin` prop ([#​26130](https://github.com/facebook/react/pull/26130) by [@​arav-ind](https://github.com/arav-ind)) - Add support for `onScrollEnd` event ([#​26789](https://github.com/facebook/react/pull/26789) by [@​devongovett](https://github.com/devongovett)) - Allow `<hr>` as child of `<select>` ([#​27632](https://github.com/facebook/react/pull/27632) by [@​SouSingh](https://github.com/SouSingh)) - Add support for Popover API ([#​27981](https://github.com/facebook/react/pull/27981) by [@​eps1lon](https://github.com/eps1lon)) - Add support for `inert` ([#​24730](https://github.com/facebook/react/pull/24730) by [@​eps1lon](https://github.com/eps1lon)) - Add support for `imageSizes` and `imageSrcSet` ([#​22550](https://github.com/facebook/react/pull/22550) by [@​eps1lon](https://github.com/eps1lon)) - Synchronously flush transitions in popstate events ([#​26025](https://github.com/facebook/react/pull/26025), [#​27559](https://github.com/facebook/react/pull/27559), [#​27505](https://github.com/facebook/react/pull/27505), [#​30759](https://github.com/facebook/react/pull/30759) by [@​tyao1](https://github.com/tyao1) and [@​acdlite](https://github.com/acdlite)) - `flushSync` exhausts queue even if something throws ([#​26366](https://github.com/facebook/react/pull/26366) by [@​acdlite](https://github.com/acdlite)) - Throw error if `react` and `react-dom` versions don’t match ([#​29236](https://github.com/facebook/react/pull/29236) by [@​acdlite](https://github.com/acdlite)) - Ensure `srcset` and `src` are assigned last on `<img>` instances ([#​30340](https://github.com/facebook/react/pull/30340) by [@​gnoff](https://github.com/gnoff)) - Javascript URLs are replaced with functions that throw errors ([#​26507](https://github.com/facebook/react/pull/26507), [#​29808](https://github.com/facebook/react/pull/29808) by [@​sebmarkbage](https://github.com/sebmarkbage) and [@​kassens](https://github.com/kassens)) - Treat toggle and beforetoggle as discrete events ([#​29176](https://github.com/facebook/react/pull/29176) by [@​eps1lon](https://github.com/eps1lon)) - Filter out empty `src` and `href` attributes (unless for `<a href=”” />`) ([#​18513](https://github.com/facebook/react/pull/18513), [#​28124](https://github.com/facebook/react/pull/28124) by [@​bvaughn](https://github.com/bvaughn) and [@​eps1lon](https://github.com/eps1lon)) - Fix unitless `scale` style property ([#​25601](https://github.com/facebook/react/pull/25601) by [@​JonnyBurger](https://github.com/JonnyBurger)) - Fix `onChange` error message for controlled `<select>` ([#​27740](https://github.com/facebook/react/pull/27740) by [@​Biki-das](https://github.com/Biki-das)) - Fix focus restore in child windows after element reorder ([#​30951](https://github.com/facebook/react/pull/30951) by [@​ling1726](https://github.com/ling1726)) - Remove `render`, `hydrate`, `findDOMNode`, `unmountComponentAtNode`, `unstable_createEventHandle`, `unstable_renderSubtreeIntoContainer`, and `unstable_runWithPriority`. Move `createRoot` and `hydrateRoot` to `react-dom/client`. ([#​28271](https://github.com/facebook/react/pull/28271) by [@​gnoff](https://github.com/gnoff)) - Remove `test-utils` ([#​28541](https://github.com/facebook/react/pull/28541) by [@​eps1lon](https://github.com/eps1lon)) - Remove `unstable_flushControlled` ([#​26397](https://github.com/facebook/react/pull/26397) by [@​kassens](https://github.com/kassens)) - Remove legacy mode ([#​28468](https://github.com/facebook/react/pull/28468) by [@​gnoff](https://github.com/gnoff)) - Remove `renderToStaticNodeStream()` ([#​28873](https://github.com/facebook/react/pull/28873) by [@​gnoff](https://github.com/gnoff)) - Remove `unstable_renderSubtreeIntoContainer` ([#​29771](https://github.com/facebook/react/pull/29771) by [@​kassens](https://github.com/kassens)) ##### React DOM Server - Stable release of React Server Components ([Many, many PRs](https://github.com/facebook/react/pulls?q=is%3Apr+is%3Aclosed+%5BFlight%5D+in%3Atitle+created%3A%3C2024-12-01+) by [@​sebmarkbage](https://github.com/sebmarkbage), [@​acdlite](https://github.com/acdlite), [@​gnoff](https://github.com/gnoff), [@​sammy-SC](https://github.com/sammy-SC), [@​gaearon](https://github.com/gaearon), [@​sophiebits](https://github.com/sophiebits), [@​unstubbable](https://github.com/unstubbable), [@​lubieowoce](https://github.com/lubieowoce)) - Support Server Actions ([#​26124](https://github.com/facebook/react/pull/26124), [#​26632](https://github.com/facebook/react/pull/26632), [#​27459](https://github.com/facebook/react/pull/27459) by [@​sebmarkbage](https://github.com/sebmarkbage) and [@​acdlite](https://github.com/acdlite)) - Changes to SSR - Add external runtime which bootstraps hydration on the client for binary transparency ([#​25437](https://github.com/facebook/react/pull/25437), [#​26169](https://github.com/facebook/react/pull/26169), [#​25499](https://github.com/facebook/react/pull/25499) by [@​MofeiZ](https://github.com/mofeiZ) and [@​acdlite](https://github.com/acdlite)) - Support subresource integrity for `bootstrapScripts` and `bootstrapModules` ([#​25104](https://github.com/facebook/react/pull/25104) by [@​gnoff](https://github.com/gnoff)) - Fix null bytes written at text chunk boundaries ([#​26228](https://github.com/facebook/react/pull/26228) by [@​sophiebits](https://github.com/sophiebits)) - Fix logic around attribute serialization ([#​26526](https://github.com/facebook/react/pull/26526) by [@​gnoff](https://github.com/gnoff)) - Fix precomputed chunk cleared on Node 18 ([#​25645](https://github.com/facebook/react/pull/25645) by [@​feedthejim](https://github.com/feedthejim)) - Optimize end tag chunks ([#​27522](https://github.com/facebook/react/pull/27522) by [@​yujunjung](https://github.com/yujunjung)) - Gracefully handle suspending in DOM configs ([#​26768](https://github.com/facebook/react/pull/26768) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Check for nullish values on ReactCustomFormAction ([#​26770](https://github.com/facebook/react/pull/26770) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Preload `bootstrapModules`, `bootstrapScripts`, and update priority queue ([#​26754](https://github.com/facebook/react/pull/26754), [#​26753](https://github.com/facebook/react/pull/26753), [#​27190](https://github.com/facebook/react/pull/27190), [#​27189](https://github.com/facebook/react/pull/27189) by [@​gnoff](https://github.com/gnoff)) - Client render the nearest child or parent suspense boundary if replay errors or is aborted ([#​27386](https://github.com/facebook/react/pull/27386) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Don't bail out of flushing if we still have pending root tasks ([#​27385](https://github.com/facebook/react/pull/27385) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Ensure Resumable State is Serializable ([#​27388](https://github.com/facebook/react/pull/27388) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Remove extra render pass when reverting to client render ([#​26445](https://github.com/facebook/react/pull/26445) by [@​acdlite](https://github.com/acdlite)) - Fix unwinding context during selective hydration ([#​25876](https://github.com/facebook/react/pull/25876) by [@​tyao1](https://github.com/tyao1)) - Stop flowing and then abort if a stream is cancelled ([#​27405](https://github.com/facebook/react/pull/27405) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Pass cancellation reason to abort ([#​27536](https://github.com/facebook/react/pull/27536) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Add `onHeaders` entrypoint option ([#​27641](https://github.com/facebook/react/pull/27641), [#​27712](https://github.com/facebook/react/pull/27712) by [@​gnoff](https://github.com/gnoff)) - Escape `<style>` and `<script>` textContent to enable rendering inner content without dangerouslySetInnerHTML ([#​28870](https://github.com/facebook/react/pull/28870), [#​28871](https://github.com/facebook/react/pull/28871) by [@​gnoff](https://github.com/gnoff)) - Fallback to client replaying actions for Blob serialization ([#​28987](https://github.com/facebook/react/pull/28987) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Render Suspense fallback if boundary contains new stylesheet during sync update ([#​28965](https://github.com/facebook/react/pull/28965) by [@​gnoff](https://github.com/gnoff)) - Fix header length tracking ([#​30327](https://github.com/facebook/react/issues/30327) by [@​gnoff](https://github.com/gnoff)) - Use `srcset` to trigger load event on mount ([#​30351](https://github.com/facebook/react/issues/30351) by [@​gnoff](https://github.com/gnoff)) - Don't perform work when closing stream ([#​30497](https://github.com/facebook/react/issues/30497) by [@​gnoff](https://github.com/gnoff)) - Allow aborting during render ([#​30488](https://github.com/facebook/react/issues/30488), [#​30730](https://github.com/facebook/react/pull/30730) by [@​gnoff](https://github.com/gnoff)) - Start initial work immediately ([#​31079](https://github.com/facebook/react/issues/31079) by [@​gnoff](https://github.com/gnoff)) - A transition flowing into a dehydrated boundary no longer suspends when showing fallback ([#​27230](https://github.com/facebook/react/pull/27230) by [@​acdlite](https://github.com/acdlite)) - Fix selective hydration triggers false update loop error ([#​27439](https://github.com/facebook/react/pull/27439) by [@​acdlite](https://github.com/acdlite)) - Warn for Child Iterator of all types but allow Generator Components ([#​28853](https://github.com/facebook/react/pull/28853) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Include regular stack trace in serialized errors ([#​28684](https://github.com/facebook/react/pull/28684), [#​28738](https://github.com/facebook/react/pull/28738) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Aborting early no longer infinitely suspends ([#​24751](https://github.com/facebook/react/pull/24751) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Fix hydration warning suppression in text comparisons ([#​24784](https://github.com/facebook/react/pull/24784) by [@​gnoff](https://github.com/gnoff)) - Changes to error handling in SSR - Add diffs to hydration warnings ([#​28502](https://github.com/facebook/react/pull/28502), [#​28512](https://github.com/facebook/react/pull/28512) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Make Error creation lazy ([#​24728](https://github.com/facebook/react/pull/24728) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Remove recoverable error when a sync update flows into a dehydrated boundary ([#​25692](https://github.com/facebook/react/pull/25692) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Don't "fix up" mismatched text content with suppressedHydrationWarning ([#​26391](https://github.com/facebook/react/pull/26391) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Fix component stacks in errors ([#​27456](https://github.com/facebook/react/pull/27456) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Add component stacks to `onError` ([#​27761](https://github.com/facebook/react/pull/27761), [#​27850](https://github.com/facebook/react/pull/27850) by [@​gnoff](https://github.com/gnoff) and [@​sebmarkbage](https://github.com/sebmarkbage)) - Throw hydration mismatch errors once ([#​28502](https://github.com/facebook/react/pull/28502) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Add Bun streaming server renderer ([#​25597](https://github.com/facebook/react/pull/25597) by [@​colinhacks](https://github.com/colinhacks)) - Add nonce support to bootstrap scripts ([#​26738](https://github.com/facebook/react/pull/26738) by [@​danieltott](https://github.com/danieltott)) - Add `crossorigin` support to bootstrap scripts ([#​26844](https://github.com/facebook/react/pull/26844) by [@​HenriqueLimas](https://github.com/HenriqueLimas)) - Support `nonce` and `fetchpriority` in preload links ([#​26826](https://github.com/facebook/react/pull/26826) by [@​liuyenwei](https://github.com/liuyenwei)) - Add `referrerPolicy` to `ReactDOM.preload()` ([#​27096](https://github.com/facebook/react/pull/27096) by [@​styfle](https://github.com/styfle)) - Add server condition for `react/jsx-dev-runtime` ([#​28921](https://github.com/facebook/react/pull/28921) by [@​himself65](https://github.com/himself65)) - Export version ([#​29596](https://github.com/facebook/react/pull/29596) by [@​unstubbable](https://github.com/unstubbable)) - Rename the secret export of Client and Server internals ([#​28786](https://github.com/facebook/react/pull/28786), [#​28789](https://github.com/facebook/react/pull/28789) by [@​sebmarkbage](https://github.com/sebmarkbage)) - Remove layout effect warning on server ([#​26395](https://github.com/facebook/react/pull/26395) by [@​rickhanlonii](https://github.com/rickhanlonii)) - Remove `errorInfo.digest` from `onRecoverableError` ([#​28222](https://github.com/facebook/react/pull/28222) by [@​gnoff](https://github.com/gnoff)) ##### ReactTestRenderer - Add deprecation error to `react-test-renderer` on web ([#​27903](https://github.com/facebook/react/pull/27903), [#​28904](https://github.com/facebook/react/pull/28904) by [@​jackpope](https://github.com/jackpope) and [@​acdlite](https://github.com/acdlite)) - Render with ConcurrentRoot on web ([#​28498](https://github.com/facebook/react/pull/28498) by [@​jackpope](https://github.com/jackpope)) - Remove `react-test-renderer/shallow` export ([#​25475](https://github.com/facebook/react/pull/25475), [#​28497](https://github.com/facebook/react/pull/28497) by [@​sebmarkbage](https://github.com/sebmarkbage) and [@​jackpope](https://github.com/jackpope)) ##### React Reconciler - Enable suspending commits without blocking render ([#​26398](https://github.com/facebook/react/pull/26398), [#​26427](https://github.com/facebook/react/pull/26427) by [@​acdlite](https://github.com/acdlite)) - Remove `prepareUpdate` ([#​26583](https://github.com/facebook/react/pull/26583), [#​27409](http://github.com/facebook/react/pull/27409) by [@​sebmarkbage](https://github.com/sebmarkbage) and [@​sophiebits](https://github.com/sophiebits)) ##### React-Is - Enable tree shaking ([#​27701](https://github.com/facebook/react/pull/27701) by [@​markerikson](https://github.com/markerikson)) - Remove `isConcurrentMode` and `isAsyncMode` methods ([#​28224](https://github.com/facebook/react/pull/28224) by [@​gaearon](https://github.com/gaearon)) ##### useSyncExternalStore - Remove React internals access ([#​29868](https://github.com/facebook/react/pull/29868) by [@​phryneas](https://github.com/phryneas)) - Fix stale selectors keeping previous store references ([#​25969](https://github.com/facebook/react/pull/25968) by [@​jellevoost](https://github.com/jellevoost)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about these updates again. --- - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate). <!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOS45OS4wIiwidXBkYXRlZEluVmVyIjoiMzkuMTEzLjAiLCJ0YXJnZXRCcmFuY2giOiJtYWluIiwibGFiZWxzIjpbImRlcGVuZGVuY2llcyJdfQ==--> Reviewed-on: https://git.tristess.app/alexandresoro/ouca-web/pulls/6 Reviewed-by: Alexandre Soro <[email protected]> Co-authored-by: renovate <[email protected]> Co-committed-by: renovate <[email protected]>
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Hoistables
In the original implementation of Float, all hoisted elements were treated like Resources. They had deduplication semantics and hydrated based on a key. This made certain kinds of hoists very challenging such as sequences of meta tags for
og:image:...metadata. The reason is each tag along is not dedupable based on only it's intrinsic properties. two identical tags may need to be included and hoisted together with preceding meta tags that describe a semantic object with a linear set of html nodes.It was clear that the concept of Browser Resources (stylesheets / scripts / preloads) did not extend universally to all hoistable tags (title, meta, other links, etc...)
Additionally while Resources benefit from deduping they suffer an inability to update because while we may have multiple rendered elements that refer to a single Resource it isn't unambiguous which element owns the props on the underlying resource. We could try merging props, but that is still really hard to reason about for authors. Instead we restrict Resource semantics to freezing the props at the time the Resource is first constructed and warn if you attempt to render the same Resource with different props via another rendered element or by updating an existing element for that Resource.
This lack of updating restriction is however way more extreme than necessary for instances that get hoisted but otherwise do not dedupe; where there is a well defined DOM instance for each rendered element. We should be able to update props on these instances.
Hoistable is a generalization of what Float tries to model for hoisting. Instead of assuming every hoistable element is a Resource we now have two distinct categories, hoistable elements and hoistable resources. As one might guess the former has semantics that match regular Host Components except the placement of the node is usually in the
<head>. The latter continues to behave how the original implementation of HostResource behaved with the first iteration of FloatHoistable Element
On the server hoistable elements render just like regular tags except the output is stored in special queues that can be emitted in the stream earlier than they otherwise would be if rendered in place. This also allow for instance the ability to render a hoistable before even rendering the tag because the queues for hoistable elements won't flush until after we have flushed the preamble (
<DOCTYPE html><html><head>).On the client, hoistable elements largely operate like HostComponents. The most notable difference is in the hydration strategy. If we are hydrating and encounter a hoistable element we will look for all tags in the document that could potentially be a match and we check whether the attributes match the props for this particular instance. We also do this in the commit phase rather than the render phase. The reason hydration can be done for HostComponents in render is the instance will be removed from the document if hydration fails so mutating it in render is safe. For hoistables the nodes are not in a hydration boundary (Root or SuspenseBoundary at time of writing) and thus if hydration fails and we may have an instance marked as bound to some Fiber when that Fiber never commits. Moving the hydration matching to commit ensures we will always succeed in pairing the hoisted DOM instance with a Fiber that has committed.
Hoistable Resource
On the server and client the semantics of Resources are largely the same they just don't apply to title, meta, and most link tags anymore. Resources hoist and dedupe via an
hrefkey and are ref counted. In a future update we will add a garbage collector so we can clean up Resources that no longer have any references<style>supportIn earlier implementations there was no support for <style> tags. This PR adds support for treating
<style href="..." precedence="...">...</style>as a Resource analagous to<link rel="stylesheet" href="..." precedence="..." />It may seem odd at first to require an href to get Resource semantics for a style tag. The rationale is that these are for inlining of actual external stylesheets as an optimization and for URI like scoping of inline styles for css-in-js libraries. The href indicates that the key space for
<style>and<link rel="stylesheet" />Resources is shared. and the precedence is there to allow for interleaving of both kinds of Style resources. This is an advanced feature that we do not expect most app developers to use directly but will be quite handy for various styling libraries and for folks who want to inline as much as possible once Fizz supports this feature.refactor notes