- Ready to learn this topic?
+ Бажаєте вивчити цю тему?
{children}
{path ? (
@@ -172,7 +190,7 @@ function LearnMore({
label="Read More"
href={path}
type="primary">
- Read More
+ Детальніше
) : null}
@@ -186,7 +204,7 @@ function LearnMore({
function ReadBlogPost({path}: {path: string}) {
return (
- Read Post
+ Переглянути публікацію
);
@@ -223,7 +241,7 @@ function YouWillLearn({
children: any;
isChapter?: boolean;
}) {
- let title = isChapter ? 'In this chapter' : 'You will learn';
+ let title = isChapter ? 'У цьому розділі' : 'Ви вивчите';
return
{children} ;
}
@@ -243,7 +261,7 @@ function AuthorCredit({
@@ -508,6 +526,8 @@ export const MDXComponents = {
MathI,
Note,
Canary,
+ Experimental,
+ ExperimentalBadge,
CanaryBadge,
NextMajor,
NextMajorBadge,
diff --git a/src/components/MDX/Recap.tsx b/src/components/MDX/Recap.tsx
index d91ed48b4..d9b4f0a6a 100644
--- a/src/components/MDX/Recap.tsx
+++ b/src/components/MDX/Recap.tsx
@@ -13,7 +13,7 @@ function Recap({children}: RecapProps) {
return (
- Recap
+ Підсумок
{children}
diff --git a/src/components/MDX/Sandpack/Console.tsx b/src/components/MDX/Sandpack/Console.tsx
index b5276fc13..fb0009209 100644
--- a/src/components/MDX/Sandpack/Console.tsx
+++ b/src/components/MDX/Sandpack/Console.tsx
@@ -165,7 +165,7 @@ export const SandpackConsole = ({visible}: {visible: boolean}) => {
className="flex items-center p-1"
onClick={() => setIsExpanded(!isExpanded)}>
-
Console ({logs.length})
+
Консоль ({logs.length})
- {isExpanded ? 'Show less' : 'Show more'}
+ {isExpanded ? 'Згорнути' : 'Розгорнути'}
)}
diff --git a/src/components/MDX/Sandpack/DownloadButton.tsx b/src/components/MDX/Sandpack/DownloadButton.tsx
index 94cf13ddc..101e6f255 100644
--- a/src/components/MDX/Sandpack/DownloadButton.tsx
+++ b/src/components/MDX/Sandpack/DownloadButton.tsx
@@ -100,9 +100,9 @@ ${css}
-
);
}
diff --git a/src/components/MDX/Sandpack/LoadingOverlay.tsx b/src/components/MDX/Sandpack/LoadingOverlay.tsx
index de883629c..b4180fae3 100644
--- a/src/components/MDX/Sandpack/LoadingOverlay.tsx
+++ b/src/components/MDX/Sandpack/LoadingOverlay.tsx
@@ -63,7 +63,7 @@ export const LoadingOverlay = ({
opacity: stillLoading ? 1 : 0,
transition: `opacity ${FADE_ANIMATION_DURATION}ms ease-out`,
}}>
-
+
{/* @ts-ignore: the OpenInCodeSandboxButton type from '@codesandbox/sandpack-react/unstyled' is incompatible with JSX in React 19 */}
diff --git a/src/components/MDX/Sandpack/OpenInCodeSandboxButton.tsx b/src/components/MDX/Sandpack/OpenInCodeSandboxButton.tsx
index a27122ed6..ae9081e8f 100644
--- a/src/components/MDX/Sandpack/OpenInCodeSandboxButton.tsx
+++ b/src/components/MDX/Sandpack/OpenInCodeSandboxButton.tsx
@@ -9,13 +9,13 @@ export const OpenInCodeSandboxButton = () => {
return (
+ title="Відкрити в CodeSandbox">
Fork
+ Відгалузити
);
};
diff --git a/src/components/MDX/Sandpack/OpenInTypeScriptPlayground.tsx b/src/components/MDX/Sandpack/OpenInTypeScriptPlayground.tsx
index 7284912e3..44354138f 100644
--- a/src/components/MDX/Sandpack/OpenInTypeScriptPlayground.tsx
+++ b/src/components/MDX/Sandpack/OpenInTypeScriptPlayground.tsx
@@ -12,7 +12,7 @@ export const OpenInTypeScriptPlaygroundButton = (props: {content: string}) => {
href={`https://www.typescriptlang.org/play#src=${encodeURIComponent(
contentWithReactImport
)}`}
- title="Open in TypeScript Playground"
+ title="Відкрити в TypeScript-пісочниці"
target="_blank"
rel="noreferrer">
{
width="1em"
height="1em"
/>
- TypeScript Playground
+ TypeScript-пісочниця
);
};
diff --git a/src/components/MDX/Sandpack/Preview.tsx b/src/components/MDX/Sandpack/Preview.tsx
index e4fe0afe4..d595c409c 100644
--- a/src/components/MDX/Sandpack/Preview.tsx
+++ b/src/components/MDX/Sandpack/Preview.tsx
@@ -189,7 +189,7 @@ export function Preview({
? 'absolute opacity-0 pointer-events-none duration-75'
: 'opacity-100 duration-150'
)}
- title="Sandbox Preview"
+ title="Попередній перегляд пісочниці"
style={{
height: iframeComputedHeight || '15px',
zIndex: isExpanded ? 'initial' : -1,
diff --git a/src/components/MDX/Sandpack/ResetButton.tsx b/src/components/MDX/Sandpack/ResetButton.tsx
index 0d1e22c80..2fbe6b157 100644
--- a/src/components/MDX/Sandpack/ResetButton.tsx
+++ b/src/components/MDX/Sandpack/ResetButton.tsx
@@ -13,9 +13,9 @@ export function ResetButton({onReset}: ResetButtonProps) {
-
);
}
diff --git a/src/components/MDX/Sandpack/template.ts b/src/components/MDX/Sandpack/template.ts
index 42f02f6a6..7fbd537e7 100644
--- a/src/components/MDX/Sandpack/template.ts
+++ b/src/components/MDX/Sandpack/template.ts
@@ -28,8 +28,8 @@ root.render(
eject: 'react-scripts eject',
},
dependencies: {
- react: '19.0.0-rc-3edc000d-20240926',
- 'react-dom': '19.0.0-rc-3edc000d-20240926',
+ react: '^19.1.0',
+ 'react-dom': '^19.1.0',
'react-scripts': '^5.0.0',
},
},
diff --git a/src/components/MDX/TeamMember.tsx b/src/components/MDX/TeamMember.tsx
index 2c2fffa73..b8675b7c5 100644
--- a/src/components/MDX/TeamMember.tsx
+++ b/src/components/MDX/TeamMember.tsx
@@ -67,7 +67,7 @@ export function TeamMember({
{twitter && (
diff --git a/src/components/PageHeading.tsx b/src/components/PageHeading.tsx
index 6000c8e51..ce4645ec1 100644
--- a/src/components/PageHeading.tsx
+++ b/src/components/PageHeading.tsx
@@ -8,10 +8,12 @@ import {H1} from './MDX/Heading';
import type {RouteTag, RouteItem} from './Layout/getRouteMeta';
import * as React from 'react';
import {IconCanary} from './Icon/IconCanary';
+import {IconExperimental} from './Icon/IconExperimental';
interface PageHeadingProps {
title: string;
- canary?: boolean;
+ version?: 'experimental' | 'canary';
+ experimental?: boolean;
status?: string;
description?: string;
tags?: RouteTag[];
@@ -21,19 +23,26 @@ interface PageHeadingProps {
function PageHeading({
title,
status,
- canary,
+ version,
tags = [],
breadcrumbs,
}: PageHeadingProps) {
+ console.log('version', version);
return (
{breadcrumbs ?
: null}
{title}
- {canary && (
+ {version === 'canary' && (
(null);
diff --git a/src/components/Tag.tsx b/src/components/Tag.tsx
index 2e63a81f6..a777724ff 100644
--- a/src/components/Tag.tsx
+++ b/src/components/Tag.tsx
@@ -7,23 +7,23 @@ import type {RouteTag} from './Layout/getRouteMeta';
const variantMap = {
foundation: {
- name: 'Foundation',
+ name: 'Початковий рівень',
classes: 'bg-yellow-50 text-white',
},
intermediate: {
- name: 'Intermediate',
+ name: 'Середній рівень',
classes: 'bg-purple-40 text-white',
},
advanced: {
- name: 'Advanced',
+ name: 'Високий рівень',
classes: 'bg-green-40 text-white',
},
experimental: {
- name: 'Experimental',
+ name: 'Експериментальне',
classes: 'bg-ui-orange text-white',
},
deprecated: {
- name: 'Deprecated',
+ name: 'Застаріле',
classes: 'bg-red-40 text-white',
},
};
diff --git a/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md b/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md
index 80fcb78e6..1aaa94ec1 100644
--- a/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md
+++ b/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md
@@ -27,7 +27,7 @@ We announced an [experimental demo of React Server Components](https://legacy.re
In particular, we’re abandoning the idea of having forked I/O libraries (eg react-fetch), and instead adopting an async/await model for better compatibility. This doesn’t technically block RSC’s release because you can also use routers for data fetching. Another change is that we’re also moving away from the file extension approach in favor of [annotating boundaries](https://github.com/reactjs/rfcs/pull/189#issuecomment-1116482278).
-We’re working together with Vercel and Shopify to unify bundler support for shared semantics in both Webpack and Vite. Before launch, we want to make sure that the semantics of RSCs are the same across the whole React ecosystem. This is the major blocker for reaching stable.
+We’re working together with Vercel and Shopify to unify bundler support for shared semantics in both webpack and Vite. Before launch, we want to make sure that the semantics of RSCs are the same across the whole React ecosystem. This is the major blocker for reaching stable.
## Asset Loading {/*asset-loading*/}
diff --git a/src/content/blog/2024/04/25/react-19-upgrade-guide.md b/src/content/blog/2024/04/25/react-19-upgrade-guide.md
index fbc4e378c..cb83a6176 100644
--- a/src/content/blog/2024/04/25/react-19-upgrade-guide.md
+++ b/src/content/blog/2024/04/25/react-19-upgrade-guide.md
@@ -24,7 +24,7 @@ To help make the upgrade to React 19 easier, we've published a `react@18.3` rele
We recommend upgrading to React 18.3 first to help identify any issues before upgrading to React 19.
-For a list of changes in 18.3 see the [Release Notes](https://github.com/facebook/react/blob/main/CHANGELOG.md).
+For a list of changes in 18.3 see the [Release Notes](https://github.com/facebook/react/blob/main/CHANGELOG.md#1830-april-25-2024).
@@ -113,7 +113,7 @@ This will run the following codemods from `react-codemod`:
- [`replace-string-ref`](https://github.com/reactjs/react-codemod?tab=readme-ov-file#replace-string-ref)
- [`replace-act-import`](https://github.com/reactjs/react-codemod?tab=readme-ov-file#replace-act-import)
- [`replace-use-form-state`](https://github.com/reactjs/react-codemod?tab=readme-ov-file#replace-use-form-state)
-- [`prop-types-typescript`](https://codemod.com/registry/react-prop-types-typescript)
+- [`prop-types-typescript`](https://github.com/reactjs/react-codemod#react-proptypes-to-prop-types)
This does not include the TypeScript changes. See [TypeScript changes](#typescript-changes) below.
diff --git a/src/content/blog/2024/10/21/react-compiler-beta-release.md b/src/content/blog/2024/10/21/react-compiler-beta-release.md
index f5a870b22..58e6b24aa 100644
--- a/src/content/blog/2024/10/21/react-compiler-beta-release.md
+++ b/src/content/blog/2024/10/21/react-compiler-beta-release.md
@@ -10,6 +10,14 @@ October 21, 2024 by [Lauren Tan](https://twitter.com/potetotes).
---
+
+
+### React Compiler is now in RC! {/*react-compiler-is-now-in-rc*/}
+
+Please see the [RC blog post](/blog/2025/04/21/react-compiler-rc) for details.
+
+
+
The React team is excited to share new updates:
diff --git a/src/content/blog/2025/02/14/sunsetting-create-react-app.md b/src/content/blog/2025/02/14/sunsetting-create-react-app.md
new file mode 100644
index 000000000..9ced6231c
--- /dev/null
+++ b/src/content/blog/2025/02/14/sunsetting-create-react-app.md
@@ -0,0 +1,320 @@
+---
+title: "Sunsetting Create React App"
+author: Matt Carroll and Ricky Hanlon
+date: 2025/02/14
+description: Today, we’re deprecating Create React App for new apps, and encouraging existing apps to migrate to a framework, or to migrate to a build tool like Vite, Parcel, or RSBuild. We’re also providing docs for when a framework isn’t a good fit for your project, you want to build your own framework, or you just want to learn how React works by building a React app from scratch.
+---
+
+February 14, 2025 by [Matt Carroll](https://twitter.com/mattcarrollcode) and [Ricky Hanlon](https://bsky.app/profile/ricky.fm)
+
+---
+
+
+
+Today, we’re deprecating [Create React App](https://create-react-app.dev/) for new apps, and encouraging existing apps to migrate to a [framework](#how-to-migrate-to-a-framework), or to [migrate to a build tool](#how-to-migrate-to-a-build-tool) like Vite, Parcel, or RSBuild.
+
+We’re also providing docs for when a framework isn’t a good fit for your project, you want to build your own framework, or you just want to learn how React works by [building a React app from scratch](/learn/build-a-react-app-from-scratch).
+
+
+
+-----
+
+When we released Create React App in 2016, there was no clear way to build a new React app.
+
+To create a React app, you had to install a bunch of tools and wire them up together yourself to support basic features like JSX, linting, and hot reloading. This was very tricky to do correctly, so the [community](https://github.com/react-boilerplate/react-boilerplate) [created](https://github.com/kriasoft/react-starter-kit) [boilerplates](https://github.com/petehunt/react-boilerplate) for [common](https://github.com/gaearon/react-hot-boilerplate) [setups](https://github.com/erikras/react-redux-universal-hot-example). However, boilerplates were difficult to update and fragmentation made it difficult for React to release new features.
+
+Create React App solved these problems by combining several tools into a single recommended configuration. This allowed apps a simple way to upgrade to new tooling features, and allowed the React team to deploy non-trivial tooling changes (Fast Refresh support, React Hooks lint rules) to the broadest possible audience.
+
+This model became so popular that there's an entire category of tools working this way today.
+
+## Deprecating Create React App {/*deprecating-create-react-app*/}
+
+Although Create React App makes it easy to get started, [there are several limitations](#limitations-of-build-tools) that make it difficult to build high performant production apps. In principle, we could solve these problems by essentially evolving it into a [framework](#why-we-recommend-frameworks).
+
+However, since Create React App currently has no active maintainers, and there are many existing frameworks that solve these problems already, we’ve decided to deprecate Create React App.
+
+Starting today, if you install a new app, you will see a deprecation warning:
+
+
+
+
+create-react-app is deprecated.
+{'\n\n'}
+You can find a list of up-to-date React frameworks on react.dev
+For more info see: react.dev/link/cra
+{'\n\n'}
+This error message will only be shown once per install.
+
+
+
+
+We've also added a deprecation notice to the Create React App [website](https://create-react-app.dev/) and GitHub [repo](https://github.com/facebook/create-react-app). Create React App will continue working in maintenance mode, and we've published a new version of Create React App to work with React 19.
+
+## How to Migrate to a Framework {/*how-to-migrate-to-a-framework*/}
+We recommend [creating new React apps](/learn/creating-a-react-app) with a framework. All the frameworks we recommend support client-side rendering ([CSR](https://developer.mozilla.org/en-US/docs/Glossary/CSR)) and single-page apps ([SPA](https://developer.mozilla.org/en-US/docs/Glossary/SPA)), and can be deployed to a CDN or static hosting service without a server.
+
+For existing apps, these guides will help you migrate to a client-only SPA:
+
+* [Next.js’ Create React App migration guide](https://nextjs.org/docs/app/building-your-application/upgrading/from-create-react-app)
+* [React Router’s framework adoption guide](https://reactrouter.com/upgrading/component-routes).
+* [Expo webpack to Expo Router migration guide](https://docs.expo.dev/router/migrate/from-expo-webpack/)
+
+## How to Migrate to a Build Tool {/*how-to-migrate-to-a-build-tool*/}
+
+If your app has unusual constraints, or you prefer to solve these problems by building your own framework, or you just want to learn how react works from scratch, you can roll your own custom setup with React using Vite, Parcel or Rsbuild.
+
+For existing apps, these guides will help you migrate to a build tool:
+
+* [Vite Create React App migration guide](https://www.robinwieruch.de/vite-create-react-app/)
+* [Parcel Create React App migration guide](https://parceljs.org/migration/cra/)
+* [Rsbuild Create React App migration guide](https://rsbuild.dev/guide/migration/cra)
+
+To help get started with Vite, Parcel or Rsbuild, we've added new docs for [Building a React App from Scratch](/learn/build-a-react-app-from-scratch).
+
+
+
+#### Do I need a framework? {/*do-i-need-a-framework*/}
+
+Most apps would benefit from a framework, but there are valid cases to build a React app from scratch. A good rule of thumb is if your app needs routing, you would probably benefit from a framework.
+
+Just like Svelte has Sveltekit, Vue has Nuxt, and Solid has SolidStart, [React recommends using a framework](#why-we-recommend-frameworks) that fully integrates routing into features like data-fetching and code-splitting out of the box. This avoids the pain of needing to write your own complex configurations and essentially build a framework yourself.
+
+However, you can always [build a React app from scratch](/learn/build-a-react-app-from-scratch) using a build tool like Vite, Parcel, or Rsbuild.
+
+
+
+Continue reading to learn more about the [limitations of build tools](#limitations-of-build-tools) and [why we recommend frameworks](#why-we-recommend-frameworks).
+
+## Limitations of Build Tools {/*limitations-of-build-tools*/}
+
+Create React App and build tools like it make it easy to get started building a React app. After running `npx create-react-app my-app`, you get a fully configured React app with a development server, linting, and a production build.
+
+For example, if you're building an internal admin tool, you can start with a landing page:
+
+```js
+export default function App() {
+ return (
+
+
Welcome to the Admin Tool!
+
+ )
+}
+```
+
+This allows you to immediately start coding in React with features like JSX, default linting rules, and a bundler to run in both development and production. However, this setup is missing the tools you need to build a real production app.
+
+Most production apps need solutions to problems like routing, data fetching, and code splitting.
+
+### Routing {/*routing*/}
+
+Create React App does not include a specific routing solution. If you're just getting started, one option is to use `useState` to switch between routes. But doing this means that you can't share links to your app - every link would go to the same page - and structuring your app becomes difficult over time:
+
+```js
+import {useState} from 'react';
+
+import Home from './Home';
+import Dashboard from './Dashboard';
+
+export default function App() {
+ // ❌ Routing in state does not create URLs
+ const [route, setRoute] = useState('home');
+ return (
+
+ {route === 'home' &&
+ )
+}
+```
+
+This is why most apps that use Create React App solve add routing with a routing library like [React Router](https://reactrouter.com/) or [Tanstack Router](https://tanstack.com/router/latest). With a routing library, you can add additional routes to the app, which provides opinions on the structure of your app, and allows you to start sharing links to routes. For example, with React Router you can define routes:
+
+```js
+import {RouterProvider, createBrowserRouter} from 'react-router';
+
+import Home from './Home';
+import Dashboard from './Dashboard';
+
+// ✅ Each route has it's own URL
+const router = createBrowserRouter([
+ {path: '/', element:
+ {data.map(item =>
{item.name}
)}
+
+ {loaderData.map(item =>
{item.name}
)}
+
+
+ Accessibility
+ Asset loading
+ Authentication
+ Caching
+
+
+ Error handling
+ Mutating data
+ Navigations
+ Optimistic updates
+
+
+ Progressive enhancement
+ Server-side rendering
+ Static site generation
+ Streaming
+
+
+
+#### Server rendering is optional {/*server-rendering-is-optional*/}
+
+The frameworks we recommend all provide the option to create a [client-side rendered (CSR)](https://developer.mozilla.org/en-US/docs/Glossary/CSR) app.
+
+In some cases, CSR is the right choice for a page, but many times it's not. Even if most of your app is client-side, there are often individual pages that could benefit from server rendering features like [static-site generation (SSG)](https://developer.mozilla.org/en-US/docs/Glossary/SSG) or [server-side rendering (SSR)](https://developer.mozilla.org/en-US/docs/Glossary/SSR), for example a Terms of Service page, or documentation.
+
+Server rendering generally sends less JavaScript to the client, and a full HTML document which produces a faster [First Contentful Paint (FCP)](https://web.dev/articles/fcp) by reducing [Total Blocking Time (TBD)](https://web.dev/articles/tbt), which can also lower [Interaction to Next Paint (INP)](https://web.dev/articles/inp). This is why the [Chrome team has encouraged](https://web.dev/articles/rendering-on-the-web) developers to consider static or server-side render over a full client-side approach to achieve the best possible performance.
+
+There are tradeoffs to using a server, and it is not always the best option for every page. Generating pages on the server incurs additional cost and takes time to generate which can increase [Time to First Byte (TTFB)](https://web.dev/articles/ttfb). The best performing apps are able to pick the right rendering strategy on a per-page basis, based on the tradeoffs of each strategy.
+
+Frameworks provide the option to use a server on any page if you want to, but do not force you to use a server. This allows you to pick the right rendering strategy for each page in your app.
+
+#### What About Server Components {/*server-components*/}
+
+The frameworks we recommend also include support for React Server Components.
+
+Server Components help solve these problems by moving routing and data fetching to the server, and allowing code splitting to be done for client components based on the data you render, instead of just the route rendered, and reducing the amount of JavaScript shipped for the best possible [loading sequence](https://www.patterns.dev/vanilla/loading-sequence).
+
+Server Components do not require a server. They can be run at build time on your CI server to create a static-site generated app (SSG) app, at runtime on a web server for a server-side rendered (SSR) app.
+
+See [Introducing zero-bundle size React Server Components](/blog/2020/12/21/data-fetching-with-react-server-components) and [the docs](/reference/rsc/server-components) for more info.
+
+
+
+
+
+#### Server Rendering is not just for SEO {/*server-rendering-is-not-just-for-seo*/}
+
+A common misunderstanding is that server rendering is only for [SEO](https://developer.mozilla.org/en-US/docs/Glossary/SEO).
+
+While server rendering can improve SEO, it also improves performance by reducing the amount of JavaScript the user needs to download and parse before they can see the content on the screen.
+
+This is why the Chrome team [has encouraged](https://web.dev/articles/rendering-on-the-web) developers to consider static or server-side render over a full client-side approach to achieve the best possible performance.
+
+
+
+---
+
+_Thank you to [Dan Abramov](https://bsky.app/profile/danabra.mov) for creating Create React App, and [Joe Haddad](https://github.com/Timer), [Ian Schmitz](https://github.com/ianschmitz), [Brody McKee](https://github.com/mrmckeb), and [many others](https://github.com/facebook/create-react-app/graphs/contributors) for maintaining Create React App over the years. Thank you to [Brooks Lybrand](https://bsky.app/profile/brookslybrand.bsky.social), [Dan Abramov](https://bsky.app/profile/danabra.mov), [Devon Govett](https://bsky.app/profile/devongovett.bsky.social), [Eli White](https://x.com/Eli_White), [Jack Herrington](https://bsky.app/profile/jherr.dev), [Joe Savona](https://x.com/en_JS), [Lauren Tan](https://bsky.app/profile/no.lol), [Lee Robinson](https://x.com/leeerob), [Mark Erikson](https://bsky.app/profile/acemarke.dev), [Ryan Florence](https://x.com/ryanflorence), [Sophie Alpert](https://bsky.app/profile/sophiebits.com), [Tanner Linsley](https://bsky.app/profile/tannerlinsley.com), and [Theo Browne](https://x.com/theo) for reviewing and providing feedback on this post._
+
diff --git a/src/content/blog/2025/04/21/react-compiler-rc.md b/src/content/blog/2025/04/21/react-compiler-rc.md
new file mode 100644
index 000000000..ecbbb8747
--- /dev/null
+++ b/src/content/blog/2025/04/21/react-compiler-rc.md
@@ -0,0 +1,128 @@
+---
+title: "React Compiler RC"
+author: Lauren Tan and Mofei Zhang
+date: 2025/04/21
+description: We are releasing the compiler's first Release Candidate (RC) today.
+
+---
+
+April 21, 2025 by [Lauren Tan](https://x.com/potetotes) and [Mofei Zhang](https://x.com/zmofei).
+
+---
+
+
+
+The React team is excited to share new updates:
+
+
+
+1. We're publishing React Compiler RC today, in preparation of the compiler's stable release.
+2. We're merging `eslint-plugin-react-compiler` into `eslint-plugin-react-hooks`.
+3. We've added support for swc and are working with oxc to support Babel-free builds.
+
+---
+
+[React Compiler](https://react.dev/learn/react-compiler) is a build-time tool that optimizes your React app through automatic memoization. Last year, we published React Compiler’s [first beta](https://react.dev/blog/2024/10/21/react-compiler-beta-release) and received lots of great feedback and contributions. We’re excited about the wins we’ve seen from folks adopting the compiler (see case studies from [Sanity Studio](https://github.com/reactwg/react-compiler/discussions/33) and [Wakelet](https://github.com/reactwg/react-compiler/discussions/52)) and are working towards a stable release.
+
+We are releasing the compiler's first Release Candidate (RC) today. The RC is intended to be a stable and near-final version of the compiler, and safe to try out in production.
+
+## Use React Compiler RC today {/*use-react-compiler-rc-today*/}
+To install the RC:
+
+npm
+
+{`npm install --save-dev --save-exact babel-plugin-react-compiler@rc`}
+
+
+pnpm
+
+{`pnpm add --save-dev --save-exact babel-plugin-react-compiler@rc`}
+
+
+yarn
+
+{`yarn add --dev --exact babel-plugin-react-compiler@rc`}
+
+
+As part of the RC, we've been making React Compiler easier to add to your projects and added optimizations to how the compiler generates memoization. React Complier now supports optional chains and array indices as dependencies. We're exploring how to infer even more dependencies like equality checks and string interpolation. These improvements ultimately result in fewer re-renders and more responsive UIs.
+
+We have also heard from the community that the ref-in-render validation sometimes has false positives. Since as a general philosophy we want you to be able to fully trust in the compiler's error messages and hints, we are turning it off by default for now. We will keep working to improve this validation, and we will re-enable it in a follow up release.
+
+You can find more details on using the Compiler in [our docs](https://react.dev/learn/react-compiler).
+
+## Feedback {/*feedback*/}
+During the RC period, we encourage all React users to try the compiler and provide feedback in the React repo. Please [open an issue](https://github.com/facebook/react/issues) if you encounter any bugs or unexpected behavior. If you have a general question or suggestion, please post them in the [React Compiler Working Group](https://github.com/reactwg/react-compiler/discussions).
+
+## Backwards Compatibility {/*backwards-compatibility*/}
+As noted in the Beta announcement, React Compiler is compatible with React 17 and up. If you are not yet on React 19, you can use React Compiler by specifying a minimum target in your compiler config, and adding `react-compiler-runtime` as a dependency. You can find docs on this [here](https://react.dev/learn/react-compiler#using-react-compiler-with-react-17-or-18).
+
+## Migrating from eslint-plugin-react-compiler to eslint-plugin-react-hooks {/*migrating-from-eslint-plugin-react-compiler-to-eslint-plugin-react-hooks*/}
+If you have already installed eslint-plugin-react-compiler, you can now remove it and use `eslint-plugin-react-hooks@6.0.0-rc.1`. Many thanks to [@michaelfaith](https://bsky.app/profile/michael.faith) for contributing to this improvement!
+
+To install:
+
+npm
+
+{`npm install --save-dev eslint-plugin-react-hooks@6.0.0-rc.1`}
+
+
+pnpm
+
+{`pnpm add --save-dev eslint-plugin-react-hooks@6.0.0-rc.1`}
+
+
+yarn
+
+{`yarn add --dev eslint-plugin-react-hooks@6.0.0-rc.1`}
+
+
+```js
+// eslint.config.js
+import * as reactHooks from 'eslint-plugin-react-hooks';
+
+export default [
+ // Flat Config (eslint 9+)
+ reactHooks.configs.recommended,
+
+ // Legacy Config
+ reactHooks.configs['recommended-latest']
+];
+```
+
+To enable the React Compiler rule, add `'react-hooks/react-compiler': 'error'` to your ESLint configuration.
+
+The linter does not require the compiler to be installed, so there's no risk in upgrading eslint-plugin-react-hooks. We recommend everyone upgrade today.
+
+## swc support (experimental) {/*swc-support-experimental*/}
+React Compiler can be installed across [several build tools](/learn/react-compiler#installation) such as Babel, Vite, and Rsbuild.
+
+In addition to those tools, we have been collaborating with Kang Dongyoon ([@kdy1dev](https://x.com/kdy1dev)) from the [swc](https://swc.rs/) team on adding additional support for React Compiler as an swc plugin. While this work isn't done, Next.js build performance should now be considerably faster when the [React Compiler is enabled in your Next.js app](https://nextjs.org/docs/app/api-reference/config/next-config-js/reactCompiler).
+
+We recommend using Next.js [15.3.1](https://github.com/vercel/next.js/releases/tag/v15.3.1) or greater to get the best build performance.
+
+Vite users can continue to use [vite-plugin-react](https://github.com/vitejs/vite-plugin-react) to enable the compiler, by adding it as a [Babel plugin](https://react.dev/learn/react-compiler#usage-with-vite). We are also working with the [oxc](https://oxc.rs/) team to [add support for the compiler](https://github.com/oxc-project/oxc/issues/10048). Once [rolldown](https://github.com/rolldown/rolldown) is officially released and supported in Vite and oxc support is added for React Compiler, we'll update the docs with information on how to migrate.
+
+## Upgrading React Compiler {/*upgrading-react-compiler*/}
+React Compiler works best when the auto-memoization applied is strictly for performance. Future versions of the compiler may change how memoization is applied, for example it could become more granular and precise.
+
+However, because product code may sometimes break the [rules of React](https://react.dev/reference/rules) in ways that aren't always statically detectable in JavaScript, changing memoization can occasionally have unexpected results. For example, a previously memoized value might be used as a dependency for a useEffect somewhere in the component tree. Changing how or whether this value is memoized can cause over or under-firing of that useEffect. While we encourage [useEffect only for synchronization](https://react.dev/learn/synchronizing-with-effects), your codebase may have useEffects that cover other use-cases such as effects that needs to only run in response to specific values changing.
+
+In other words, changing memoization may under rare circumstances cause unexpected behavior. For this reason, we recommend following the Rules of React and employing continuous end-to-end testing of your app so you can upgrade the compiler with confidence and identify any rules of React violations that might cause issues.
+
+If you don't have good test coverage, we recommend pinning the compiler to an exact version (eg `19.1.0`) rather than a SemVer range (eg `^19.1.0`). You can do this by passing the `--save-exact` (npm/pnpm) or `--exact` flags (yarn) when upgrading the compiler. You should then do any upgrades of the compiler manually, taking care to check that your app still works as expected.
+
+## Roadmap to Stable {/*roadmap-to-stable*/}
+*This is not a final roadmap, and is subject to change.*
+
+After a period of final feedback from the community on the RC, we plan on a Stable Release for the compiler.
+
+* ✅ Experimental: Released at React Conf 2024, primarily for feedback from application developers.
+* ✅ Public Beta: Available today, for feedback from library authors.
+* ✅ Release Candidate (RC): React Compiler works for the majority of rule-following apps and libraries without issue.
+* General Availability: After final feedback period from the community.
+
+Post-Stable, we plan to add more compiler optimizations and improvements. This includes both continual improvements to automatic memoization, and new optimizations altogether, with minimal to no change of product code. Each upgrade will continue to improve performance and add better handling of diverse JavaScript and React patterns.
+
+---
+
+Thanks to [Joe Savona](https://x.com/en_JS), [Jason Bonta](https://x.com/someextent), [Jimmy Lai](https://x.com/feedthejim), and [Kang Dongyoon](https://x.com/kdy1dev) (@kdy1dev) for reviewing and editing this post.
diff --git a/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md b/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md
new file mode 100644
index 000000000..e4bb25a4a
--- /dev/null
+++ b/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md
@@ -0,0 +1,14358 @@
+---
+title: "React Labs: View Transitions, Activity, and more"
+author: Ricky Hanlon
+date: 2025/04/23
+description: In React Labs posts, we write about projects in active research and development. In this post, we're sharing two new experimental features that are ready to try today, and updates on other areas we're working on now.
+---
+
+April 23, 2025 by [Ricky Hanlon](https://twitter.com/rickhanlonii)
+
+---
+
+
+
+In React Labs posts, we write about projects in active research and development. In this post, we're sharing two new experimental features that are ready to try today, and updates on other areas we're working on now.
+
+
+
+
+
+
+React Conf 2025 is scheduled for October 7–8 in Henderson, Nevada!
+
+We're looking for speakers to help us create talks about the features covered in this post. If you're interested in speaking at ReactConf, [please apply here](https://forms.reform.app/react-conf/call-for-speakers/) (no talk proposal required).
+
+For more info on tickets, free streaming, sponsoring, and more, see [the React Conf website](https://conf.react.dev).
+
+
+
+Today, we're excited to release documentation for two new experimental features that are ready for testing:
+
+- [View Transitions](#view-transitions)
+- [Activity](#activity)
+
+We're also sharing updates on new features currently in development:
+- [React Performance Tracks](#react-performance-tracks)
+- [Compiler IDE Extension](#compiler-ide-extension)
+- [Automatic Effect Dependencies](#automatic-effect-dependencies)
+- [Fragment Refs](#fragment-refs)
+- [Concurrent Stores](#concurrent-stores)
+
+---
+
+# New Experimental Features {/*new-experimental-features*/}
+
+View Transitions and Activity are now ready for testing in `react@experimental`. These features have been tested in production and are stable, but the final API may still change as we incorporate feedback.
+
+You can try them by upgrading React packages to the most recent experimental version:
+
+- `react@experimental`
+- `react-dom@experimental`
+
+Read on to learn how to use these features in your app, or check out the newly published docs:
+
+- [``](/reference/react/ViewTransition): A component that lets you activate an animation for a Transition.
+- [`addTransitionType`](/reference/react/addTransitionType): A function that allows you to specify the cause of a Transition.
+- [``](/reference/react/Activity): A component that lets you hide and show parts of the UI.
+
+## View Transitions {/*view-transitions*/}
+
+React View Transitions are a new experimental feature that makes it easier to add animations to UI transitions in your app. Under-the-hood, these animations use the new [`startViewTransition`](https://developer.mozilla.org/en-US/docs/Web/API/Document/startViewTransition) API available in most modern browsers.
+
+To opt-in to animating an element, wrap it in the new `` component:
+
+```js
+// "what" to animate.
+
+ animate me
+
+```
+
+This new component lets you declaratively define "what" to animate when an animation is activated.
+
+You can define "when" to animate by using one of these three triggers for a View Transition:
+
+```js
+// "when" to animate.
+
+// Transitions
+startTransition(() => setState(...));
+
+// Deferred Values
+const deferred = useDeferredValue(value);
+
+// Suspense
+Loading...
+
+```
+
+By default, these animations use the [default CSS animations for View Transitions](https://developer.mozilla.org/en-US/docs/Web/API/View_Transition_API/Using#customizing_your_animations) applied (typically a smooth cross-fade). You can use [view transition pseudo-selectors](https://developer.mozilla.org/en-US/docs/Web/API/View_Transition_API/Using#the_view_transition_pseudo-element_tree) to define "how" the animation runs. For example, you can use `*` to change the default animation for all transitions:
+
+```
+// "how" to animate.
+::view-transition-old(*) {
+ animation: 300ms ease-out fade-out;
+}
+::view-transition-new(*) {
+ animation: 300ms ease-in fade-in;
+}
+```
+
+When the DOM updates due to an animation trigger—like `startTransition`, `useDeferredValue`, or a `Suspense` fallback switching to content—React will use [declarative heuristics](/reference/react/ViewTransition#viewtransition) to automatically determine which `` components to activate for the animation. The browser will then run the animation that's defined in CSS.
+
+If you're familiar with the browser's View Transition API and want to know how React supports it, check out [How does `` Work](/reference/react/ViewTransition#how-does-viewtransition-work) in the docs.
+
+In this post, let's take a look at a few examples of how to use View Transitions.
+
+We'll start with this app, which doesn't animate any of the following interactions:
+- Click a video to view the details.
+- Click "back" to go back to the feed.
+- Type in the list to filter the videos.
+
+
+
+```js src/App.js active
+import TalkDetails from './Details'; import Home from './Home'; import {useRouter} from './router';
+
+export default function App() {
+ const {url} = useRouter();
+
+ // 🚩This version doesn't include any animations yet
+ return url === '/' ? {details.title}
+ {details.description}
+
+ );
+}
+
+function VideoInfoFallback() {
+ return (
+ <>
+
+
+
+ );
+}
+
+export default function Details() {
+ const { url, navigateBack } = useRouter();
+ const videoId = url.split("/").pop();
+ const video = use(fetchVideo(videoId));
+
+ return (
+ {
+ navigateBack("/");
+ }}
+ >
+
+ }
+ >
+
+
+
+
+
+ );
+}
+
+```
+
+```js src/Home.js
+import { Video } from "./Videos";
+import Layout from "./Layout";
+import { fetchVideos } from "./data";
+import { useId, useState, use } from "react";
+import { IconSearch } from "./Icons";
+
+function SearchInput({ value, onChange }) {
+ const id = useId();
+ return (
+
+ );
+}
+
+function filterVideos(videos, query) {
+ const keywords = query
+ .toLowerCase()
+ .split(" ")
+ .filter((s) => s !== "");
+ if (keywords.length === 0) {
+ return videos;
+ }
+ return videos.filter((video) => {
+ const words = (video.title + " " + video.description)
+ .toLowerCase()
+ .split(" ");
+ return keywords.every((kw) => words.some((w) => w.includes(kw)));
+ });
+}
+
+export default function Home() {
+ const videos = use(fetchVideos());
+ const count = videos.length;
+ const [searchText, setSearchText] = useState("");
+ const foundVideos = filterVideos(videos, searchText);
+ return (
+
{count} Videos }>
+
+ {foundVideos.length === 0 && (
+
No results
+ )}
+
+ {foundVideos.map((video) => (
+
+
+
+
+
+ );
+}
+
+export function PauseIcon() {
+ return (
+
+
+ );
+}
+
+export function PlayIcon() {
+ return (
+
+
+ );
+}
+export function Heart({liked, animate}) {
+ return (
+ <>
+
+
+
+
+ {liked ? (
+
+
+ );
+}
+
+export function IconSearch(props) {
+ return (
+
+
+ );
+}
+```
+
+```js src/Layout.js
+import { useIsNavPending } from "./router";
+
+export default function Page({ heading, children }) {
+ const isPending = useIsNavPending();
+ return (
+
+
+
+ {heading}
+ {isPending &&
+
+
+
+
{
+ const nextIsLiked = !isLiked;
+ if (nextIsLiked) {
+ likedVideos.add(video.id);
+ } else {
+ likedVideos.delete(video.id);
+ }
+ setAnimate(true);
+ setIsLiked(nextIsLiked);
+ }}>
+
+ );
+}
+```
+
+```js src/Videos.js
+import { useState } from "react";
+import LikeButton from "./LikeButton";
+import { useRouter } from "./router";
+import { PauseIcon, PlayIcon } from "./Icons";
+import { startTransition } from "react";
+
+export function VideoControls() {
+ const [isPlaying, setIsPlaying] = useState(false);
+
+ return (
+
+ startTransition(() => {
+ setIsPlaying((p) => !p);
+ })
+ }
+ >
+ {isPlaying ?
+ );
+}
+
+export function Thumbnail({ video, children }) {
+ return (
+
+ {children}
+
+ );
+}
+
+export function Video({ video }) {
+ const { navigate } = useRouter();
+
+ return (
+
+
{
+ e.preventDefault();
+ navigate(`/video/${video.id}`);
+ }}
+ >
+
+
+
+
{video.title}
+
{video.description}
+
+
+
+
+ {children}
+
+ );
+}
+```
+
+```css src/styles.css
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2");
+ font-weight: 400;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2");
+ font-weight: 500;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 600;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 700;
+ font-style: normal;
+ font-display: swap;
+}
+
+* {
+ box-sizing: border-box;
+}
+
+html {
+ background-image: url(https://react.dev/images/meta-gradient-dark.png);
+ background-size: 100%;
+ background-position: -100%;
+ background-color: rgb(64 71 86);
+ background-repeat: no-repeat;
+ height: 100%;
+ width: 100%;
+}
+
+body {
+ font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
+ padding: 10px 0 10px 0;
+ margin: 0;
+ display: flex;
+ justify-content: center;
+}
+
+#root {
+ flex: 1 1;
+ height: auto;
+ background-color: #fff;
+ border-radius: 10px;
+ max-width: 450px;
+ min-height: 600px;
+ padding-bottom: 10px;
+}
+
+h1 {
+ margin-top: 0;
+ font-size: 22px;
+}
+
+h2 {
+ margin-top: 0;
+ font-size: 20px;
+}
+
+h3 {
+ margin-top: 0;
+ font-size: 18px;
+}
+
+h4 {
+ margin-top: 0;
+ font-size: 16px;
+}
+
+h5 {
+ margin-top: 0;
+ font-size: 14px;
+}
+
+h6 {
+ margin-top: 0;
+ font-size: 12px;
+}
+
+code {
+ font-size: 1.2em;
+}
+
+ul {
+ padding-inline-start: 20px;
+}
+
+.sr-only {
+ position: absolute;
+ width: 1px;
+ height: 1px;
+ padding: 0;
+ margin: -1px;
+ overflow: hidden;
+ clip: rect(0, 0, 0, 0);
+ white-space: nowrap;
+ border-width: 0;
+}
+
+.absolute {
+ position: absolute;
+}
+
+.overflow-visible {
+ overflow: visible;
+}
+
+.visible {
+ overflow: visible;
+}
+
+.fit {
+ width: fit-content;
+}
+
+
+/* Layout */
+.page {
+ display: flex;
+ flex-direction: column;
+ height: 100%;
+}
+
+.top-hero {
+ height: 200px;
+ display: flex;
+ justify-content: center;
+ align-items: center;
+ background-image: conic-gradient(
+ from 90deg at -10% 100%,
+ #2b303b 0deg,
+ #2b303b 90deg,
+ #16181d 1turn
+ );
+}
+
+.bottom {
+ flex: 1;
+ overflow: auto;
+}
+
+.top-nav {
+ display: flex;
+ align-items: center;
+ justify-content: space-between;
+ margin-bottom: 0;
+ padding: 0 12px;
+ top: 0;
+ width: 100%;
+ height: 44px;
+ color: #23272f;
+ font-weight: 700;
+ font-size: 20px;
+ z-index: 100;
+ cursor: default;
+}
+
+.content {
+ padding: 0 12px;
+ margin-top: 4px;
+}
+
+
+.loader {
+ color: #23272f;
+ font-size: 3px;
+ width: 1em;
+ margin-right: 18px;
+ height: 1em;
+ border-radius: 50%;
+ position: relative;
+ text-indent: -9999em;
+ animation: loading-spinner 1.3s infinite linear;
+ animation-delay: 200ms;
+ transform: translateZ(0);
+}
+
+@keyframes loading-spinner {
+ 0%,
+ 100% {
+ box-shadow: 0 -3em 0 0.2em,
+ 2em -2em 0 0em, 3em 0 0 -1em,
+ 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 0;
+ }
+ 12.5% {
+ box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em,
+ 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 25% {
+ box-shadow: 0 -3em 0 -0.5em,
+ 2em -2em 0 0, 3em 0 0 0.2em,
+ 2em 2em 0 0, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 37.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em,
+ -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 50% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em,
+ -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 62.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0,
+ -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em;
+ }
+ 75% {
+ box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0;
+ }
+ 87.5% {
+ box-shadow: 0em -3em 0 0, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em;
+ }
+}
+
+/* LikeButton */
+.like-button {
+ outline-offset: 2px;
+ position: relative;
+ display: flex;
+ align-items: center;
+ justify-content: center;
+ width: 2.5rem;
+ height: 2.5rem;
+ cursor: pointer;
+ border-radius: 9999px;
+ border: none;
+ outline: none 2px;
+ color: #5e687e;
+ background: none;
+}
+
+.like-button:focus {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+}
+
+.like-button:active {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+ transform: scaleX(0.95) scaleY(0.95);
+}
+
+.like-button:hover {
+ background-color: #f6f7f9;
+}
+
+.like-button.liked {
+ color: #a6423a;
+}
+
+/* Icons */
+@keyframes circle {
+ 0% {
+ transform: scale(0);
+ stroke-width: 16px;
+ }
+
+ 50% {
+ transform: scale(.5);
+ stroke-width: 16px;
+ }
+
+ to {
+ transform: scale(1);
+ stroke-width: 0;
+ }
+}
+
+.circle {
+ color: rgba(166, 66, 58, .5);
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4,0,.2,1);
+}
+
+.circle.liked.animate {
+ animation: circle .3s forwards;
+}
+
+.heart {
+ width: 1.5rem;
+ height: 1.5rem;
+}
+
+.heart.liked {
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4, 0, .2, 1);
+}
+
+.heart.liked.animate {
+ animation: scale .35s ease-in-out forwards;
+}
+
+.control-icon {
+ color: hsla(0, 0%, 100%, .5);
+ filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08));
+}
+
+.chevron-left {
+ margin-top: 2px;
+ rotate: 90deg;
+}
+
+
+/* Video */
+.thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 8rem;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.thumbnail.blue {
+ background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491);
+}
+
+.thumbnail.red {
+ background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491);
+}
+
+.thumbnail.green {
+ background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491);
+}
+
+.thumbnail.purple {
+ background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491);
+}
+
+.thumbnail.yellow {
+ background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491);
+}
+
+.thumbnail.gray {
+ background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491);
+}
+
+.video {
+ display: flex;
+ flex-direction: row;
+ gap: 0.75rem;
+ align-items: center;
+}
+
+.video .link {
+ display: flex;
+ flex-direction: row;
+ flex: 1 1 0;
+ gap: 0.125rem;
+ outline-offset: 4px;
+ cursor: pointer;
+}
+
+.video .info {
+ display: flex;
+ flex-direction: column;
+ justify-content: center;
+ margin-left: 8px;
+ gap: 0.125rem;
+}
+
+.video .info:hover {
+ text-decoration: underline;
+}
+
+.video-title {
+ font-size: 15px;
+ line-height: 1.25;
+ font-weight: 700;
+ color: #23272f;
+}
+
+.video-description {
+ color: #5e687e;
+ font-size: 13px;
+}
+
+/* Details */
+.details .thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 100%;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.video-details-title {
+ margin-top: 8px;
+}
+
+.video-details-speaker {
+ display: flex;
+ gap: 8px;
+ margin-top: 10px
+}
+
+.back {
+ display: flex;
+ align-items: center;
+ margin-left: -5px;
+ cursor: pointer;
+}
+
+.back:hover {
+ text-decoration: underline;
+}
+
+.info-title {
+ font-size: 1.5rem;
+ font-weight: 700;
+ line-height: 1.25;
+ margin: 8px 0 0 0 ;
+}
+
+.info-description {
+ margin: 8px 0 0 0;
+}
+
+.controls {
+ cursor: pointer;
+}
+
+.fallback {
+ background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat;
+ background-size: 800px 104px;
+ display: block;
+ line-height: 1.25;
+ margin: 8px 0 0 0;
+ border-radius: 5px;
+ overflow: hidden;
+
+ animation: 1s linear 1s infinite shimmer;
+ animation-delay: 300ms;
+ animation-duration: 1s;
+ animation-fill-mode: forwards;
+ animation-iteration-count: infinite;
+ animation-name: shimmer;
+ animation-timing-function: linear;
+}
+
+
+.fallback.title {
+ width: 130px;
+ height: 30px;
+
+}
+
+.fallback.description {
+ width: 150px;
+ height: 21px;
+}
+
+@keyframes shimmer {
+ 0% {
+ background-position: -468px 0;
+ }
+
+ 100% {
+ background-position: 468px 0;
+ }
+}
+
+.search {
+ margin-bottom: 10px;
+}
+.search-input {
+ width: 100%;
+ position: relative;
+}
+
+.search-icon {
+ position: absolute;
+ top: 0;
+ bottom: 0;
+ inset-inline-start: 0;
+ display: flex;
+ align-items: center;
+ padding-inline-start: 1rem;
+ pointer-events: none;
+ color: #99a1b3;
+}
+
+.search-input input {
+ display: flex;
+ padding-inline-start: 2.75rem;
+ padding-top: 10px;
+ padding-bottom: 10px;
+ width: 100%;
+ text-align: start;
+ background-color: rgb(235 236 240);
+ outline: 2px solid transparent;
+ cursor: pointer;
+ border: none;
+ align-items: center;
+ color: rgb(35 39 47);
+ border-radius: 9999px;
+ vertical-align: middle;
+ font-size: 15px;
+}
+
+.search-input input:hover, .search-input input:active {
+ background-color: rgb(235 236 240/ 0.8);
+ color: rgb(35 39 47/ 0.8);
+}
+
+/* Home */
+.video-list {
+ position: relative;
+}
+
+.video-list .videos {
+ display: flex;
+ flex-direction: column;
+ gap: 1rem;
+ overflow-y: auto;
+ height: 100%;
+}
+```
+
+```js src/index.js hidden
+import React, {StrictMode} from 'react';
+import {createRoot} from 'react-dom/client';
+import './styles.css';
+
+import App from './App';
+import {Router} from './router';
+
+const root = createRoot(document.getElementById('root'));
+root.render(
+
+
+
+
+);
+```
+
+```json package.json hidden
+{
+ "dependencies": {
+ "react": "experimental",
+ "react-dom": "experimental",
+ "react-scripts": "latest"
+ },
+ "scripts": {
+ "start": "react-scripts start",
+ "build": "react-scripts build",
+ "test": "react-scripts test --env=jsdom",
+ "eject": "react-scripts eject"
+ }
+}
+```
+
+
+
+
+
+#### View Transitions do not replace CSS and JS driven animations {/*view-transitions-do-not-replace-css-and-js-driven-animations*/}
+
+View Transitions are meant to be used for UI transitions such as navigation, expanding, opening, or re-ordering. They are not meant to replace all the animations in your app.
+
+In our example app above, notice that there are already animations when you click the "like" button and in the Suspense fallback glimmer. These are good use cases for CSS animations because they are animating a specific element.
+
+
+
+### Animating navigations {/*animating-navigations*/}
+
+Our app includes a Suspense-enabled router, with [page transitions already marked as Transitions](/reference/react/useTransition#building-a-suspense-enabled-router), which means navigations are performed with `startTransition`:
+
+```js
+function navigate(url) {
+ startTransition(() => {
+ go(url);
+ });
+}
+```
+
+`startTransition` is a View Transition trigger, so we can add `` to animate between pages:
+
+```js
+// "what" to animate
+
+ {url === '/' ?
+```
+
+When the `url` changes, the `` and new route are rendered. Since the `` was updated inside of `startTransition`, the `` is activated for an animation.
+
+
+By default, View Transitions include the browser default cross-fade animation. Adding this to our example, we now have a cross-fade whenever we navigate between pages:
+
+
+
+```js src/App.js active
+import {unstable_ViewTransition as ViewTransition} from 'react'; import Details from './Details'; import Home from './Home'; import {useRouter} from './router';
+
+export default function App() {
+ const {url} = useRouter();
+
+ // Use ViewTransition to animate between pages.
+ // No additional CSS needed by default.
+ return (
+
+ {url === '/' ?
+ );
+}
+```
+
+```js src/Details.js hidden
+import { fetchVideo, fetchVideoDetails } from "./data";
+import { Thumbnail, VideoControls } from "./Videos";
+import { useRouter } from "./router";
+import Layout from "./Layout";
+import { use, Suspense } from "react";
+import { ChevronLeft } from "./Icons";
+
+function VideoInfo({ id }) {
+ const details = use(fetchVideoDetails(id));
+ return (
+ <>
+ {details.title}
+ {details.description}
+
+ );
+}
+
+function VideoInfoFallback() {
+ return (
+ <>
+
+
+
+ );
+}
+
+export default function Details() {
+ const { url, navigateBack } = useRouter();
+ const videoId = url.split("/").pop();
+ const video = use(fetchVideo(videoId));
+
+ return (
+ {
+ navigateBack("/");
+ }}
+ >
+
+ }
+ >
+
+
+
+
+
+ );
+}
+
+```
+
+```js src/Home.js hidden
+import { Video } from "./Videos";
+import Layout from "./Layout";
+import { fetchVideos } from "./data";
+import { useId, useState, use } from "react";
+import { IconSearch } from "./Icons";
+
+function SearchInput({ value, onChange }) {
+ const id = useId();
+ return (
+
+ );
+}
+
+function filterVideos(videos, query) {
+ const keywords = query
+ .toLowerCase()
+ .split(" ")
+ .filter((s) => s !== "");
+ if (keywords.length === 0) {
+ return videos;
+ }
+ return videos.filter((video) => {
+ const words = (video.title + " " + video.description)
+ .toLowerCase()
+ .split(" ");
+ return keywords.every((kw) => words.some((w) => w.includes(kw)));
+ });
+}
+
+export default function Home() {
+ const videos = use(fetchVideos());
+ const count = videos.length;
+ const [searchText, setSearchText] = useState("");
+ const foundVideos = filterVideos(videos, searchText);
+ return (
+ {count} Videos }>
+
+ {foundVideos.length === 0 && (
+
No results
+ )}
+
+ {foundVideos.map((video) => (
+
+
+
+
+
+ );
+}
+
+export function PauseIcon() {
+ return (
+
+
+ );
+}
+
+export function PlayIcon() {
+ return (
+
+
+ );
+}
+export function Heart({liked, animate}) {
+ return (
+ <>
+
+
+
+
+ {liked ? (
+
+
+ );
+}
+
+export function IconSearch(props) {
+ return (
+
+
+ );
+}
+```
+
+```js src/Layout.js
+import {unstable_ViewTransition as ViewTransition} from 'react'; import { useIsNavPending } from "./router";
+
+export default function Page({ heading, children }) {
+ const isPending = useIsNavPending();
+
+ return (
+
+
+
+ {heading}
+ {isPending &&
+
+ {/* Opt-out of ViewTransition for the content. */}
+ {/* Content can define it's own ViewTransition. */}
+
+
+
+
{
+ const nextIsLiked = !isLiked;
+ if (nextIsLiked) {
+ likedVideos.add(video.id);
+ } else {
+ likedVideos.delete(video.id);
+ }
+ setAnimate(true);
+ setIsLiked(nextIsLiked);
+ }}>
+
+ );
+}
+```
+
+```js src/Videos.js hidden
+import { useState } from "react";
+import LikeButton from "./LikeButton";
+import { useRouter } from "./router";
+import { PauseIcon, PlayIcon } from "./Icons";
+import { startTransition } from "react";
+
+export function VideoControls() {
+ const [isPlaying, setIsPlaying] = useState(false);
+
+ return (
+
+ startTransition(() => {
+ setIsPlaying((p) => !p);
+ })
+ }
+ >
+ {isPlaying ?
+ );
+}
+
+export function Thumbnail({ video, children }) {
+ return (
+
+ {children}
+
+ );
+}
+
+export function Video({ video }) {
+ const { navigate } = useRouter();
+
+ return (
+
+
{
+ e.preventDefault();
+ navigate(`/video/${video.id}`);
+ }}
+ >
+
+
+
+
{video.title}
+
{video.description}
+
+
+
+
+ {children}
+
+ );
+}
+
+const RouterContext = createContext({ url: "/", params: {} });
+
+export function useRouter() {
+ return use(RouterContext);
+}
+
+export function useIsNavPending() {
+ return use(RouterContext).isPending;
+}
+```
+
+```css src/styles.css hidden
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2");
+ font-weight: 400;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2");
+ font-weight: 500;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 600;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 700;
+ font-style: normal;
+ font-display: swap;
+}
+
+* {
+ box-sizing: border-box;
+}
+
+html {
+ background-image: url(https://react.dev/images/meta-gradient-dark.png);
+ background-size: 100%;
+ background-position: -100%;
+ background-color: rgb(64 71 86);
+ background-repeat: no-repeat;
+ height: 100%;
+ width: 100%;
+}
+
+body {
+ font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
+ padding: 10px 0 10px 0;
+ margin: 0;
+ display: flex;
+ justify-content: center;
+}
+
+#root {
+ flex: 1 1;
+ height: auto;
+ background-color: #fff;
+ border-radius: 10px;
+ max-width: 450px;
+ min-height: 600px;
+ padding-bottom: 10px;
+}
+
+h1 {
+ margin-top: 0;
+ font-size: 22px;
+}
+
+h2 {
+ margin-top: 0;
+ font-size: 20px;
+}
+
+h3 {
+ margin-top: 0;
+ font-size: 18px;
+}
+
+h4 {
+ margin-top: 0;
+ font-size: 16px;
+}
+
+h5 {
+ margin-top: 0;
+ font-size: 14px;
+}
+
+h6 {
+ margin-top: 0;
+ font-size: 12px;
+}
+
+code {
+ font-size: 1.2em;
+}
+
+ul {
+ padding-inline-start: 20px;
+}
+
+.sr-only {
+ position: absolute;
+ width: 1px;
+ height: 1px;
+ padding: 0;
+ margin: -1px;
+ overflow: hidden;
+ clip: rect(0, 0, 0, 0);
+ white-space: nowrap;
+ border-width: 0;
+}
+
+.absolute {
+ position: absolute;
+}
+
+.overflow-visible {
+ overflow: visible;
+}
+
+.visible {
+ overflow: visible;
+}
+
+.fit {
+ width: fit-content;
+}
+
+
+/* Layout */
+.page {
+ display: flex;
+ flex-direction: column;
+ height: 100%;
+}
+
+.top-hero {
+ height: 200px;
+ display: flex;
+ justify-content: center;
+ align-items: center;
+ background-image: conic-gradient(
+ from 90deg at -10% 100%,
+ #2b303b 0deg,
+ #2b303b 90deg,
+ #16181d 1turn
+ );
+}
+
+.bottom {
+ flex: 1;
+ overflow: auto;
+}
+
+.top-nav {
+ display: flex;
+ align-items: center;
+ justify-content: space-between;
+ margin-bottom: 0;
+ padding: 0 12px;
+ top: 0;
+ width: 100%;
+ height: 44px;
+ color: #23272f;
+ font-weight: 700;
+ font-size: 20px;
+ z-index: 100;
+ cursor: default;
+}
+
+.content {
+ padding: 0 12px;
+ margin-top: 4px;
+}
+
+
+.loader {
+ color: #23272f;
+ font-size: 3px;
+ width: 1em;
+ margin-right: 18px;
+ height: 1em;
+ border-radius: 50%;
+ position: relative;
+ text-indent: -9999em;
+ animation: loading-spinner 1.3s infinite linear;
+ animation-delay: 200ms;
+ transform: translateZ(0);
+}
+
+@keyframes loading-spinner {
+ 0%,
+ 100% {
+ box-shadow: 0 -3em 0 0.2em,
+ 2em -2em 0 0em, 3em 0 0 -1em,
+ 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 0;
+ }
+ 12.5% {
+ box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em,
+ 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 25% {
+ box-shadow: 0 -3em 0 -0.5em,
+ 2em -2em 0 0, 3em 0 0 0.2em,
+ 2em 2em 0 0, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 37.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em,
+ -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 50% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em,
+ -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 62.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0,
+ -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em;
+ }
+ 75% {
+ box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0;
+ }
+ 87.5% {
+ box-shadow: 0em -3em 0 0, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em;
+ }
+}
+
+/* LikeButton */
+.like-button {
+ outline-offset: 2px;
+ position: relative;
+ display: flex;
+ align-items: center;
+ justify-content: center;
+ width: 2.5rem;
+ height: 2.5rem;
+ cursor: pointer;
+ border-radius: 9999px;
+ border: none;
+ outline: none 2px;
+ color: #5e687e;
+ background: none;
+}
+
+.like-button:focus {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+}
+
+.like-button:active {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+ transform: scaleX(0.95) scaleY(0.95);
+}
+
+.like-button:hover {
+ background-color: #f6f7f9;
+}
+
+.like-button.liked {
+ color: #a6423a;
+}
+
+/* Icons */
+@keyframes circle {
+ 0% {
+ transform: scale(0);
+ stroke-width: 16px;
+ }
+
+ 50% {
+ transform: scale(.5);
+ stroke-width: 16px;
+ }
+
+ to {
+ transform: scale(1);
+ stroke-width: 0;
+ }
+}
+
+.circle {
+ color: rgba(166, 66, 58, .5);
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4,0,.2,1);
+}
+
+.circle.liked.animate {
+ animation: circle .3s forwards;
+}
+
+.heart {
+ width: 1.5rem;
+ height: 1.5rem;
+}
+
+.heart.liked {
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4, 0, .2, 1);
+}
+
+.heart.liked.animate {
+ animation: scale .35s ease-in-out forwards;
+}
+
+.control-icon {
+ color: hsla(0, 0%, 100%, .5);
+ filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08));
+}
+
+.chevron-left {
+ margin-top: 2px;
+ rotate: 90deg;
+}
+
+
+/* Video */
+.thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 8rem;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.thumbnail.blue {
+ background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491);
+}
+
+.thumbnail.red {
+ background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491);
+}
+
+.thumbnail.green {
+ background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491);
+}
+
+.thumbnail.purple {
+ background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491);
+}
+
+.thumbnail.yellow {
+ background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491);
+}
+
+.thumbnail.gray {
+ background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491);
+}
+
+.video {
+ display: flex;
+ flex-direction: row;
+ gap: 0.75rem;
+ align-items: center;
+}
+
+.video .link {
+ display: flex;
+ flex-direction: row;
+ flex: 1 1 0;
+ gap: 0.125rem;
+ outline-offset: 4px;
+ cursor: pointer;
+}
+
+.video .info {
+ display: flex;
+ flex-direction: column;
+ justify-content: center;
+ margin-left: 8px;
+ gap: 0.125rem;
+}
+
+.video .info:hover {
+ text-decoration: underline;
+}
+
+.video-title {
+ font-size: 15px;
+ line-height: 1.25;
+ font-weight: 700;
+ color: #23272f;
+}
+
+.video-description {
+ color: #5e687e;
+ font-size: 13px;
+}
+
+/* Details */
+.details .thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 100%;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.video-details-title {
+ margin-top: 8px;
+}
+
+.video-details-speaker {
+ display: flex;
+ gap: 8px;
+ margin-top: 10px
+}
+
+.back {
+ display: flex;
+ align-items: center;
+ margin-left: -5px;
+ cursor: pointer;
+}
+
+.back:hover {
+ text-decoration: underline;
+}
+
+.info-title {
+ font-size: 1.5rem;
+ font-weight: 700;
+ line-height: 1.25;
+ margin: 8px 0 0 0 ;
+}
+
+.info-description {
+ margin: 8px 0 0 0;
+}
+
+.controls {
+ cursor: pointer;
+}
+
+.fallback {
+ background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat;
+ background-size: 800px 104px;
+ display: block;
+ line-height: 1.25;
+ margin: 8px 0 0 0;
+ border-radius: 5px;
+ overflow: hidden;
+
+ animation: 1s linear 1s infinite shimmer;
+ animation-delay: 300ms;
+ animation-duration: 1s;
+ animation-fill-mode: forwards;
+ animation-iteration-count: infinite;
+ animation-name: shimmer;
+ animation-timing-function: linear;
+}
+
+
+.fallback.title {
+ width: 130px;
+ height: 30px;
+
+}
+
+.fallback.description {
+ width: 150px;
+ height: 21px;
+}
+
+@keyframes shimmer {
+ 0% {
+ background-position: -468px 0;
+ }
+
+ 100% {
+ background-position: 468px 0;
+ }
+}
+
+.search {
+ margin-bottom: 10px;
+}
+.search-input {
+ width: 100%;
+ position: relative;
+}
+
+.search-icon {
+ position: absolute;
+ top: 0;
+ bottom: 0;
+ inset-inline-start: 0;
+ display: flex;
+ align-items: center;
+ padding-inline-start: 1rem;
+ pointer-events: none;
+ color: #99a1b3;
+}
+
+.search-input input {
+ display: flex;
+ padding-inline-start: 2.75rem;
+ padding-top: 10px;
+ padding-bottom: 10px;
+ width: 100%;
+ text-align: start;
+ background-color: rgb(235 236 240);
+ outline: 2px solid transparent;
+ cursor: pointer;
+ border: none;
+ align-items: center;
+ color: rgb(35 39 47);
+ border-radius: 9999px;
+ vertical-align: middle;
+ font-size: 15px;
+}
+
+.search-input input:hover, .search-input input:active {
+ background-color: rgb(235 236 240/ 0.8);
+ color: rgb(35 39 47/ 0.8);
+}
+
+/* Home */
+.video-list {
+ position: relative;
+}
+
+.video-list .videos {
+ display: flex;
+ flex-direction: column;
+ gap: 1rem;
+ overflow-y: auto;
+ height: 100%;
+}
+```
+
+```js src/index.js hidden
+import React, {StrictMode} from 'react';
+import {createRoot} from 'react-dom/client';
+import './styles.css';
+
+import App from './App';
+import {Router} from './router';
+
+const root = createRoot(document.getElementById('root'));
+root.render(
+
+
+
+
+);
+```
+
+```json package.json hidden
+{
+ "dependencies": {
+ "react": "experimental",
+ "react-dom": "experimental",
+ "react-scripts": "latest"
+ },
+ "scripts": {
+ "start": "react-scripts start",
+ "build": "react-scripts build",
+ "test": "react-scripts test --env=jsdom",
+ "eject": "react-scripts eject"
+ }
+}
+```
+
+
+
+Since our router already updates the route using `startTransition`, this one line change to add `` activates with the default cross-fade animation.
+
+If you're curious how this works, see the docs for [How does `` work?](/reference/react/ViewTransition#how-does-viewtransition-work)
+
+
+
+#### Opting out of `` animations {/*opting-out-of-viewtransition-animations*/}
+
+In this example, we're wrapping the root of the app in `` for simplicity, but this means that all transitions in the app will be animated, which can lead to unexpected animations.
+
+To fix, we're wrapping route children with `"none"` so each page can control its own animation:
+
+```js
+// Layout.js
+
+ {children}
+
+```
+
+In practice, navigations should be done via "enter" and "exit" props, or by using Transition Types.
+
+
+
+### Customizing animations {/*customizing-animations*/}
+
+By default, `` includes the default cross-fade from the browser.
+
+To customize animations, you can provide props to the `` component to specify which animations to use, based on [how the `` activates](/reference/react/ViewTransition#props).
+
+For example, we can slow down the `default` cross fade animation:
+
+```js
+
+
+```
+
+And define `slow-fade` in CSS using [view transition classes](/reference/react/ViewTransition#view-transition-classes):
+
+```css
+::view-transition-old(.slow-fade) {
+ animation-duration: 500ms;
+}
+
+::view-transition-new(.slow-fade) {
+ animation-duration: 500ms;
+}
+```
+
+Now, the cross fade is slower:
+
+
+
+```js src/App.js active
+import { unstable_ViewTransition as ViewTransition } from "react";
+import Details from "./Details";
+import Home from "./Home";
+import { useRouter } from "./router";
+
+export default function App() {
+ const { url } = useRouter();
+
+ // Define a default animation of .slow-fade.
+ // See animations.css for the animation definiton.
+ return (
+
+ {url === '/' ?
+ );
+}
+```
+
+```js src/Details.js hidden
+import { fetchVideo, fetchVideoDetails } from "./data";
+import { Thumbnail, VideoControls } from "./Videos";
+import { useRouter } from "./router";
+import Layout from "./Layout";
+import { use, Suspense } from "react";
+import { ChevronLeft } from "./Icons";
+
+function VideoInfo({ id }) {
+ const details = use(fetchVideoDetails(id));
+ return (
+ <>
+ {details.title}
+ {details.description}
+
+ );
+}
+
+function VideoInfoFallback() {
+ return (
+ <>
+
+
+
+ );
+}
+
+export default function Details() {
+ const { url, navigateBack } = useRouter();
+ const videoId = url.split("/").pop();
+ const video = use(fetchVideo(videoId));
+
+ return (
+ {
+ navigateBack("/");
+ }}
+ >
+
+ }
+ >
+
+
+
+
+
+ );
+}
+
+```
+
+```js src/Home.js hidden
+import { Video } from "./Videos";
+import Layout from "./Layout";
+import { fetchVideos } from "./data";
+import { useId, useState, use } from "react";
+import { IconSearch } from "./Icons";
+
+function SearchInput({ value, onChange }) {
+ const id = useId();
+ return (
+
+ );
+}
+
+function filterVideos(videos, query) {
+ const keywords = query
+ .toLowerCase()
+ .split(" ")
+ .filter((s) => s !== "");
+ if (keywords.length === 0) {
+ return videos;
+ }
+ return videos.filter((video) => {
+ const words = (video.title + " " + video.description)
+ .toLowerCase()
+ .split(" ");
+ return keywords.every((kw) => words.some((w) => w.includes(kw)));
+ });
+}
+
+export default function Home() {
+ const videos = use(fetchVideos());
+ const count = videos.length;
+ const [searchText, setSearchText] = useState("");
+ const foundVideos = filterVideos(videos, searchText);
+ return (
+ {count} Videos }>
+
+
+ {foundVideos.length === 0 && (
+
No results
+ )}
+
+ {foundVideos.map((video) => (
+
+
+
+ );
+}
+
+```
+
+```js src/Icons.js hidden
+export function ChevronLeft() {
+ return (
+
+
+
+
+ );
+}
+
+export function PauseIcon() {
+ return (
+
+
+ );
+}
+
+export function PlayIcon() {
+ return (
+
+
+ );
+}
+export function Heart({liked, animate}) {
+ return (
+ <>
+
+
+
+
+ {liked ? (
+
+
+ );
+}
+
+export function IconSearch(props) {
+ return (
+
+
+ );
+}
+```
+
+```js src/Layout.js hidden
+import {unstable_ViewTransition as ViewTransition} from 'react'; import { useIsNavPending } from "./router";
+
+export default function Page({ heading, children }) {
+ const isPending = useIsNavPending();
+
+ return (
+
+
+
+ {heading}
+ {isPending &&
+
+ {/* Opt-out of ViewTransition for the content. */}
+ {/* Content can define it's own ViewTransition. */}
+
+
+
+
+ );
+}
+```
+
+```js src/LikeButton.js hidden
+import {useState} from 'react';
+import {Heart} from './Icons';
+
+// A hack since we don't actually have a backend.
+// Unlike local state, this survives videos being filtered.
+const likedVideos = new Set();
+
+export default function LikeButton({video}) {
+ const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id));
+ const [animate, setAnimate] = useState(false);
+ return (
+
{
+ const nextIsLiked = !isLiked;
+ if (nextIsLiked) {
+ likedVideos.add(video.id);
+ } else {
+ likedVideos.delete(video.id);
+ }
+ setAnimate(true);
+ setIsLiked(nextIsLiked);
+ }}>
+
+ );
+}
+```
+
+```js src/Videos.js hidden
+import { useState } from "react";
+import LikeButton from "./LikeButton";
+import { useRouter } from "./router";
+import { PauseIcon, PlayIcon } from "./Icons";
+import { startTransition } from "react";
+
+export function VideoControls() {
+ const [isPlaying, setIsPlaying] = useState(false);
+
+ return (
+
+ startTransition(() => {
+ setIsPlaying((p) => !p);
+ })
+ }
+ >
+ {isPlaying ?
+ );
+}
+
+export function Thumbnail({ video, children }) {
+ return (
+
+ {children}
+
+ );
+}
+
+export function Video({ video }) {
+ const { navigate } = useRouter();
+
+ return (
+
+
{
+ e.preventDefault();
+ navigate(`/video/${video.id}`);
+ }}
+ >
+
+
+
+
{video.title}
+
{video.description}
+
+
+
+
+ );
+}
+```
+
+
+```js src/data.js hidden
+const videos = [
+ {
+ id: '1',
+ title: 'First video',
+ description: 'Video description',
+ image: 'blue',
+ },
+ {
+ id: '2',
+ title: 'Second video',
+ description: 'Video description',
+ image: 'red',
+ },
+ {
+ id: '3',
+ title: 'Third video',
+ description: 'Video description',
+ image: 'green',
+ },
+ {
+ id: '4',
+ title: 'Fourth video',
+ description: 'Video description',
+ image: 'purple',
+ },
+ {
+ id: '5',
+ title: 'Fifth video',
+ description: 'Video description',
+ image: 'yellow',
+ },
+ {
+ id: '6',
+ title: 'Sixth video',
+ description: 'Video description',
+ image: 'gray',
+ },
+];
+
+let videosCache = new Map();
+let videoCache = new Map();
+let videoDetailsCache = new Map();
+const VIDEO_DELAY = 1;
+const VIDEO_DETAILS_DELAY = 1000;
+export function fetchVideos() {
+ if (videosCache.has(0)) {
+ return videosCache.get(0);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos);
+ }, VIDEO_DELAY);
+ });
+ videosCache.set(0, promise);
+ return promise;
+}
+
+export function fetchVideo(id) {
+ if (videoCache.has(id)) {
+ return videoCache.get(id);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos.find((video) => video.id === id));
+ }, VIDEO_DELAY);
+ });
+ videoCache.set(id, promise);
+ return promise;
+}
+
+export function fetchVideoDetails(id) {
+ if (videoDetailsCache.has(id)) {
+ return videoDetailsCache.get(id);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos.find((video) => video.id === id));
+ }, VIDEO_DETAILS_DELAY);
+ });
+ videoDetailsCache.set(id, promise);
+ return promise;
+}
+```
+
+```js src/router.js hidden
+import {
+ useState,
+ createContext,
+ use,
+ useTransition,
+ useLayoutEffect,
+ useEffect,
+} from "react";
+
+const RouterContext = createContext({ url: "/", params: {} });
+
+export function useRouter() {
+ return use(RouterContext);
+}
+
+export function useIsNavPending() {
+ return use(RouterContext).isPending;
+}
+
+export function Router({ children }) {
+ const [routerState, setRouterState] = useState({
+ pendingNav: () => {},
+ url: document.location.pathname,
+ });
+ const [isPending, startTransition] = useTransition();
+
+ function go(url) {
+ setRouterState({
+ url,
+ pendingNav() {
+ window.history.pushState({}, "", url);
+ },
+ });
+ }
+ function navigate(url) {
+ // Update router state in transition.
+ startTransition(() => {
+ go(url);
+ });
+ }
+
+ function navigateBack(url) {
+ // Update router state in transition.
+ startTransition(() => {
+ go(url);
+ });
+ }
+
+ useEffect(() => {
+ function handlePopState() {
+ // This should not animate because restoration has to be synchronous.
+ // Even though it's a transition.
+ startTransition(() => {
+ setRouterState({
+ url: document.location.pathname + document.location.search,
+ pendingNav() {
+ // Noop. URL has already updated.
+ },
+ });
+ });
+ }
+ window.addEventListener("popstate", handlePopState);
+ return () => {
+ window.removeEventListener("popstate", handlePopState);
+ };
+ }, []);
+ const pendingNav = routerState.pendingNav;
+ useLayoutEffect(() => {
+ pendingNav();
+ }, [pendingNav]);
+
+ return (
+
+ {children}
+
+ );
+}
+```
+
+```css src/styles.css hidden
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2");
+ font-weight: 400;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2");
+ font-weight: 500;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 600;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 700;
+ font-style: normal;
+ font-display: swap;
+}
+
+* {
+ box-sizing: border-box;
+}
+
+html {
+ background-image: url(https://react.dev/images/meta-gradient-dark.png);
+ background-size: 100%;
+ background-position: -100%;
+ background-color: rgb(64 71 86);
+ background-repeat: no-repeat;
+ height: 100%;
+ width: 100%;
+}
+
+body {
+ font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
+ padding: 10px 0 10px 0;
+ margin: 0;
+ display: flex;
+ justify-content: center;
+}
+
+#root {
+ flex: 1 1;
+ height: auto;
+ background-color: #fff;
+ border-radius: 10px;
+ max-width: 450px;
+ min-height: 600px;
+ padding-bottom: 10px;
+}
+
+h1 {
+ margin-top: 0;
+ font-size: 22px;
+}
+
+h2 {
+ margin-top: 0;
+ font-size: 20px;
+}
+
+h3 {
+ margin-top: 0;
+ font-size: 18px;
+}
+
+h4 {
+ margin-top: 0;
+ font-size: 16px;
+}
+
+h5 {
+ margin-top: 0;
+ font-size: 14px;
+}
+
+h6 {
+ margin-top: 0;
+ font-size: 12px;
+}
+
+code {
+ font-size: 1.2em;
+}
+
+ul {
+ padding-inline-start: 20px;
+}
+
+.sr-only {
+ position: absolute;
+ width: 1px;
+ height: 1px;
+ padding: 0;
+ margin: -1px;
+ overflow: hidden;
+ clip: rect(0, 0, 0, 0);
+ white-space: nowrap;
+ border-width: 0;
+}
+
+.absolute {
+ position: absolute;
+}
+
+.overflow-visible {
+ overflow: visible;
+}
+
+.visible {
+ overflow: visible;
+}
+
+.fit {
+ width: fit-content;
+}
+
+
+/* Layout */
+.page {
+ display: flex;
+ flex-direction: column;
+ height: 100%;
+}
+
+.top-hero {
+ height: 200px;
+ display: flex;
+ justify-content: center;
+ align-items: center;
+ background-image: conic-gradient(
+ from 90deg at -10% 100%,
+ #2b303b 0deg,
+ #2b303b 90deg,
+ #16181d 1turn
+ );
+}
+
+.bottom {
+ flex: 1;
+ overflow: auto;
+}
+
+.top-nav {
+ display: flex;
+ align-items: center;
+ justify-content: space-between;
+ margin-bottom: 0;
+ padding: 0 12px;
+ top: 0;
+ width: 100%;
+ height: 44px;
+ color: #23272f;
+ font-weight: 700;
+ font-size: 20px;
+ z-index: 100;
+ cursor: default;
+}
+
+.content {
+ padding: 0 12px;
+ margin-top: 4px;
+}
+
+
+.loader {
+ color: #23272f;
+ font-size: 3px;
+ width: 1em;
+ margin-right: 18px;
+ height: 1em;
+ border-radius: 50%;
+ position: relative;
+ text-indent: -9999em;
+ animation: loading-spinner 1.3s infinite linear;
+ animation-delay: 200ms;
+ transform: translateZ(0);
+}
+
+@keyframes loading-spinner {
+ 0%,
+ 100% {
+ box-shadow: 0 -3em 0 0.2em,
+ 2em -2em 0 0em, 3em 0 0 -1em,
+ 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 0;
+ }
+ 12.5% {
+ box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em,
+ 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 25% {
+ box-shadow: 0 -3em 0 -0.5em,
+ 2em -2em 0 0, 3em 0 0 0.2em,
+ 2em 2em 0 0, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 37.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em,
+ -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 50% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em,
+ -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 62.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0,
+ -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em;
+ }
+ 75% {
+ box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0;
+ }
+ 87.5% {
+ box-shadow: 0em -3em 0 0, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em;
+ }
+}
+
+/* LikeButton */
+.like-button {
+ outline-offset: 2px;
+ position: relative;
+ display: flex;
+ align-items: center;
+ justify-content: center;
+ width: 2.5rem;
+ height: 2.5rem;
+ cursor: pointer;
+ border-radius: 9999px;
+ border: none;
+ outline: none 2px;
+ color: #5e687e;
+ background: none;
+}
+
+.like-button:focus {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+}
+
+.like-button:active {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+ transform: scaleX(0.95) scaleY(0.95);
+}
+
+.like-button:hover {
+ background-color: #f6f7f9;
+}
+
+.like-button.liked {
+ color: #a6423a;
+}
+
+/* Icons */
+@keyframes circle {
+ 0% {
+ transform: scale(0);
+ stroke-width: 16px;
+ }
+
+ 50% {
+ transform: scale(.5);
+ stroke-width: 16px;
+ }
+
+ to {
+ transform: scale(1);
+ stroke-width: 0;
+ }
+}
+
+.circle {
+ color: rgba(166, 66, 58, .5);
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4,0,.2,1);
+}
+
+.circle.liked.animate {
+ animation: circle .3s forwards;
+}
+
+.heart {
+ width: 1.5rem;
+ height: 1.5rem;
+}
+
+.heart.liked {
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4, 0, .2, 1);
+}
+
+.heart.liked.animate {
+ animation: scale .35s ease-in-out forwards;
+}
+
+.control-icon {
+ color: hsla(0, 0%, 100%, .5);
+ filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08));
+}
+
+.chevron-left {
+ margin-top: 2px;
+ rotate: 90deg;
+}
+
+
+/* Video */
+.thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 8rem;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.thumbnail.blue {
+ background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491);
+}
+
+.thumbnail.red {
+ background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491);
+}
+
+.thumbnail.green {
+ background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491);
+}
+
+.thumbnail.purple {
+ background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491);
+}
+
+.thumbnail.yellow {
+ background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491);
+}
+
+.thumbnail.gray {
+ background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491);
+}
+
+.video {
+ display: flex;
+ flex-direction: row;
+ gap: 0.75rem;
+ align-items: center;
+}
+
+.video .link {
+ display: flex;
+ flex-direction: row;
+ flex: 1 1 0;
+ gap: 0.125rem;
+ outline-offset: 4px;
+ cursor: pointer;
+}
+
+.video .info {
+ display: flex;
+ flex-direction: column;
+ justify-content: center;
+ margin-left: 8px;
+ gap: 0.125rem;
+}
+
+.video .info:hover {
+ text-decoration: underline;
+}
+
+.video-title {
+ font-size: 15px;
+ line-height: 1.25;
+ font-weight: 700;
+ color: #23272f;
+}
+
+.video-description {
+ color: #5e687e;
+ font-size: 13px;
+}
+
+/* Details */
+.details .thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 100%;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.video-details-title {
+ margin-top: 8px;
+}
+
+.video-details-speaker {
+ display: flex;
+ gap: 8px;
+ margin-top: 10px
+}
+
+.back {
+ display: flex;
+ align-items: center;
+ margin-left: -5px;
+ cursor: pointer;
+}
+
+.back:hover {
+ text-decoration: underline;
+}
+
+.info-title {
+ font-size: 1.5rem;
+ font-weight: 700;
+ line-height: 1.25;
+ margin: 8px 0 0 0 ;
+}
+
+.info-description {
+ margin: 8px 0 0 0;
+}
+
+.controls {
+ cursor: pointer;
+}
+
+.fallback {
+ background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat;
+ background-size: 800px 104px;
+ display: block;
+ line-height: 1.25;
+ margin: 8px 0 0 0;
+ border-radius: 5px;
+ overflow: hidden;
+
+ animation: 1s linear 1s infinite shimmer;
+ animation-delay: 300ms;
+ animation-duration: 1s;
+ animation-fill-mode: forwards;
+ animation-iteration-count: infinite;
+ animation-name: shimmer;
+ animation-timing-function: linear;
+}
+
+
+.fallback.title {
+ width: 130px;
+ height: 30px;
+
+}
+
+.fallback.description {
+ width: 150px;
+ height: 21px;
+}
+
+@keyframes shimmer {
+ 0% {
+ background-position: -468px 0;
+ }
+
+ 100% {
+ background-position: 468px 0;
+ }
+}
+
+.search {
+ margin-bottom: 10px;
+}
+.search-input {
+ width: 100%;
+ position: relative;
+}
+
+.search-icon {
+ position: absolute;
+ top: 0;
+ bottom: 0;
+ inset-inline-start: 0;
+ display: flex;
+ align-items: center;
+ padding-inline-start: 1rem;
+ pointer-events: none;
+ color: #99a1b3;
+}
+
+.search-input input {
+ display: flex;
+ padding-inline-start: 2.75rem;
+ padding-top: 10px;
+ padding-bottom: 10px;
+ width: 100%;
+ text-align: start;
+ background-color: rgb(235 236 240);
+ outline: 2px solid transparent;
+ cursor: pointer;
+ border: none;
+ align-items: center;
+ color: rgb(35 39 47);
+ border-radius: 9999px;
+ vertical-align: middle;
+ font-size: 15px;
+}
+
+.search-input input:hover, .search-input input:active {
+ background-color: rgb(235 236 240/ 0.8);
+ color: rgb(35 39 47/ 0.8);
+}
+
+/* Home */
+.video-list {
+ position: relative;
+}
+
+.video-list .videos {
+ display: flex;
+ flex-direction: column;
+ gap: 1rem;
+ overflow-y: auto;
+ height: 100%;
+}
+```
+
+
+```css src/animations.css
+/* Define .slow-fade using view transition classes */
+::view-transition-old(.slow-fade) {
+ animation-duration: 500ms;
+}
+
+::view-transition-new(.slow-fade) {
+ animation-duration: 500ms;
+}
+```
+
+```js src/index.js hidden
+import React, {StrictMode} from 'react';
+import {createRoot} from 'react-dom/client';
+import './styles.css';
+import './animations.css';
+
+import App from './App';
+import {Router} from './router';
+
+const root = createRoot(document.getElementById('root'));
+root.render(
+
+
+
+
+);
+```
+
+```json package.json hidden
+{
+ "dependencies": {
+ "react": "experimental",
+ "react-dom": "experimental",
+ "react-scripts": "latest"
+ },
+ "scripts": {
+ "start": "react-scripts start",
+ "build": "react-scripts build",
+ "test": "react-scripts test --env=jsdom",
+ "eject": "react-scripts eject"
+ }
+}
+```
+
+
+
+See [Styling View Transitions](/reference/react/ViewTransition#styling-view-transitions) for a full guide on styling `
`.
+
+### Shared Element Transitions {/*shared-element-transitions*/}
+
+When two pages include the same element, often you want to animate it from one page to the next.
+
+To do this you can add a unique `name` to the ``:
+
+```js
+
+
+```
+
+Now the video thumbnail animates between the two pages:
+
+
+
+```js src/App.js
+import { unstable_ViewTransition as ViewTransition } from "react";
+import Details from "./Details";
+import Home from "./Home";
+import { useRouter } from "./router";
+
+export default function App() {
+ const { url } = useRouter();
+
+ // Keeping our default slow-fade.
+ // This allows the content not in the shared
+ // element transition to cross-fade.
+ return (
+
+ {url === "/" ?
+ );
+}
+```
+
+```js src/Details.js hidden
+import { fetchVideo, fetchVideoDetails } from "./data";
+import { Thumbnail, VideoControls } from "./Videos";
+import { useRouter } from "./router";
+import Layout from "./Layout";
+import { use, Suspense } from "react";
+import { ChevronLeft } from "./Icons";
+
+function VideoInfo({ id }) {
+ const details = use(fetchVideoDetails(id));
+ return (
+ <>
+ {details.title}
+ {details.description}
+
+ );
+}
+
+function VideoInfoFallback() {
+ return (
+ <>
+
+
+
+ );
+}
+
+export default function Details() {
+ const { url, navigateBack } = useRouter();
+ const videoId = url.split("/").pop();
+ const video = use(fetchVideo(videoId));
+
+ return (
+ {
+ navigateBack("/");
+ }}
+ >
+
+ }
+ >
+
+
+
+
+
+ );
+}
+
+```
+
+```js src/Home.js hidden
+import { Video } from "./Videos";
+import Layout from "./Layout";
+import { fetchVideos } from "./data";
+import { useId, useState, use } from "react";
+import { IconSearch } from "./Icons";
+
+function SearchInput({ value, onChange }) {
+ const id = useId();
+ return (
+
+ );
+}
+
+function filterVideos(videos, query) {
+ const keywords = query
+ .toLowerCase()
+ .split(" ")
+ .filter((s) => s !== "");
+ if (keywords.length === 0) {
+ return videos;
+ }
+ return videos.filter((video) => {
+ const words = (video.title + " " + video.description)
+ .toLowerCase()
+ .split(" ");
+ return keywords.every((kw) => words.some((w) => w.includes(kw)));
+ });
+}
+
+export default function Home() {
+ const videos = use(fetchVideos());
+ const count = videos.length;
+ const [searchText, setSearchText] = useState("");
+ const foundVideos = filterVideos(videos, searchText);
+ return (
+
{count} Videos }>
+
+
+ {foundVideos.length === 0 && (
+
No results
+ )}
+
+ {foundVideos.map((video) => (
+
+
+
+ );
+}
+
+```
+
+```js src/Icons.js hidden
+export function ChevronLeft() {
+ return (
+
+
+
+
+ );
+}
+
+export function PauseIcon() {
+ return (
+
+
+ );
+}
+
+export function PlayIcon() {
+ return (
+
+
+ );
+}
+export function Heart({liked, animate}) {
+ return (
+ <>
+
+
+
+
+ {liked ? (
+
+
+ );
+}
+
+export function IconSearch(props) {
+ return (
+
+
+ );
+}
+```
+
+```js src/Layout.js hidden
+import {unstable_ViewTransition as ViewTransition} from 'react'; import { useIsNavPending } from "./router";
+
+export default function Page({ heading, children }) {
+ const isPending = useIsNavPending();
+
+ return (
+
+
+
+ {heading}
+ {isPending &&
+
+ {/* Opt-out of ViewTransition for the content. */}
+ {/* Content can define it's own ViewTransition. */}
+
+
+
+
+ );
+}
+```
+
+```js src/LikeButton.js hidden
+import {useState} from 'react';
+import {Heart} from './Icons';
+
+// A hack since we don't actually have a backend.
+// Unlike local state, this survives videos being filtered.
+const likedVideos = new Set();
+
+export default function LikeButton({video}) {
+ const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id));
+ const [animate, setAnimate] = useState(false);
+ return (
+
{
+ const nextIsLiked = !isLiked;
+ if (nextIsLiked) {
+ likedVideos.add(video.id);
+ } else {
+ likedVideos.delete(video.id);
+ }
+ setAnimate(true);
+ setIsLiked(nextIsLiked);
+ }}>
+
+ );
+}
+```
+
+```js src/Videos.js active
+import { useState, unstable_ViewTransition as ViewTransition } from "react"; import LikeButton from "./LikeButton"; import { useRouter } from "./router"; import { PauseIcon, PlayIcon } from "./Icons"; import { startTransition } from "react";
+
+export function Thumbnail({ video, children }) {
+ // Add a name to animate with a shared element transition.
+ // This uses the default animation, no additional css needed.
+ return (
+
+
+ {children}
+
+
+ );
+}
+
+export function VideoControls() {
+ const [isPlaying, setIsPlaying] = useState(false);
+
+ return (
+
+ startTransition(() => {
+ setIsPlaying((p) => !p);
+ })
+ }
+ >
+ {isPlaying ?
+ );
+}
+
+export function Video({ video }) {
+ const { navigate } = useRouter();
+
+ return (
+
+
{
+ e.preventDefault();
+ navigate(`/video/${video.id}`);
+ }}
+ >
+
+
+
+
{video.title}
+
{video.description}
+
+
+
+
+ );
+}
+```
+
+
+```js src/data.js hidden
+const videos = [
+ {
+ id: '1',
+ title: 'First video',
+ description: 'Video description',
+ image: 'blue',
+ },
+ {
+ id: '2',
+ title: 'Second video',
+ description: 'Video description',
+ image: 'red',
+ },
+ {
+ id: '3',
+ title: 'Third video',
+ description: 'Video description',
+ image: 'green',
+ },
+ {
+ id: '4',
+ title: 'Fourth video',
+ description: 'Video description',
+ image: 'purple',
+ },
+ {
+ id: '5',
+ title: 'Fifth video',
+ description: 'Video description',
+ image: 'yellow',
+ },
+ {
+ id: '6',
+ title: 'Sixth video',
+ description: 'Video description',
+ image: 'gray',
+ },
+];
+
+let videosCache = new Map();
+let videoCache = new Map();
+let videoDetailsCache = new Map();
+const VIDEO_DELAY = 1;
+const VIDEO_DETAILS_DELAY = 1000;
+export function fetchVideos() {
+ if (videosCache.has(0)) {
+ return videosCache.get(0);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos);
+ }, VIDEO_DELAY);
+ });
+ videosCache.set(0, promise);
+ return promise;
+}
+
+export function fetchVideo(id) {
+ if (videoCache.has(id)) {
+ return videoCache.get(id);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos.find((video) => video.id === id));
+ }, VIDEO_DELAY);
+ });
+ videoCache.set(id, promise);
+ return promise;
+}
+
+export function fetchVideoDetails(id) {
+ if (videoDetailsCache.has(id)) {
+ return videoDetailsCache.get(id);
+ }
+ const promise = new Promise((resolve) => {
+ setTimeout(() => {
+ resolve(videos.find((video) => video.id === id));
+ }, VIDEO_DETAILS_DELAY);
+ });
+ videoDetailsCache.set(id, promise);
+ return promise;
+}
+```
+
+```js src/router.js hidden
+import {
+ useState,
+ createContext,
+ use,
+ useTransition,
+ useLayoutEffect,
+ useEffect,
+} from "react";
+
+const RouterContext = createContext({ url: "/", params: {} });
+
+export function useRouter() {
+ return use(RouterContext);
+}
+
+export function useIsNavPending() {
+ return use(RouterContext).isPending;
+}
+
+export function Router({ children }) {
+ const [routerState, setRouterState] = useState({
+ pendingNav: () => {},
+ url: document.location.pathname,
+ });
+ const [isPending, startTransition] = useTransition();
+
+ function go(url) {
+ setRouterState({
+ url,
+ pendingNav() {
+ window.history.pushState({}, "", url);
+ },
+ });
+ }
+ function navigate(url) {
+ // Update router state in transition.
+ startTransition(() => {
+ go(url);
+ });
+ }
+
+ function navigateBack(url) {
+ // Update router state in transition.
+ startTransition(() => {
+ go(url);
+ });
+ }
+
+ useEffect(() => {
+ function handlePopState() {
+ // This should not animate because restoration has to be synchronous.
+ // Even though it's a transition.
+ startTransition(() => {
+ setRouterState({
+ url: document.location.pathname + document.location.search,
+ pendingNav() {
+ // Noop. URL has already updated.
+ },
+ });
+ });
+ }
+ window.addEventListener("popstate", handlePopState);
+ return () => {
+ window.removeEventListener("popstate", handlePopState);
+ };
+ }, []);
+ const pendingNav = routerState.pendingNav;
+ useLayoutEffect(() => {
+ pendingNav();
+ }, [pendingNav]);
+
+ return (
+
+ {children}
+
+ );
+}
+```
+
+```css src/styles.css hidden
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2");
+ font-weight: 400;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2");
+ font-weight: 500;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 600;
+ font-style: normal;
+ font-display: swap;
+}
+
+@font-face {
+ font-family: Optimistic Text;
+ src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2");
+ font-weight: 700;
+ font-style: normal;
+ font-display: swap;
+}
+
+* {
+ box-sizing: border-box;
+}
+
+html {
+ background-image: url(https://react.dev/images/meta-gradient-dark.png);
+ background-size: 100%;
+ background-position: -100%;
+ background-color: rgb(64 71 86);
+ background-repeat: no-repeat;
+ height: 100%;
+ width: 100%;
+}
+
+body {
+ font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
+ padding: 10px 0 10px 0;
+ margin: 0;
+ display: flex;
+ justify-content: center;
+}
+
+#root {
+ flex: 1 1;
+ height: auto;
+ background-color: #fff;
+ border-radius: 10px;
+ max-width: 450px;
+ min-height: 600px;
+ padding-bottom: 10px;
+}
+
+h1 {
+ margin-top: 0;
+ font-size: 22px;
+}
+
+h2 {
+ margin-top: 0;
+ font-size: 20px;
+}
+
+h3 {
+ margin-top: 0;
+ font-size: 18px;
+}
+
+h4 {
+ margin-top: 0;
+ font-size: 16px;
+}
+
+h5 {
+ margin-top: 0;
+ font-size: 14px;
+}
+
+h6 {
+ margin-top: 0;
+ font-size: 12px;
+}
+
+code {
+ font-size: 1.2em;
+}
+
+ul {
+ padding-inline-start: 20px;
+}
+
+.sr-only {
+ position: absolute;
+ width: 1px;
+ height: 1px;
+ padding: 0;
+ margin: -1px;
+ overflow: hidden;
+ clip: rect(0, 0, 0, 0);
+ white-space: nowrap;
+ border-width: 0;
+}
+
+.absolute {
+ position: absolute;
+}
+
+.overflow-visible {
+ overflow: visible;
+}
+
+.visible {
+ overflow: visible;
+}
+
+.fit {
+ width: fit-content;
+}
+
+
+/* Layout */
+.page {
+ display: flex;
+ flex-direction: column;
+ height: 100%;
+}
+
+.top-hero {
+ height: 200px;
+ display: flex;
+ justify-content: center;
+ align-items: center;
+ background-image: conic-gradient(
+ from 90deg at -10% 100%,
+ #2b303b 0deg,
+ #2b303b 90deg,
+ #16181d 1turn
+ );
+}
+
+.bottom {
+ flex: 1;
+ overflow: auto;
+}
+
+.top-nav {
+ display: flex;
+ align-items: center;
+ justify-content: space-between;
+ margin-bottom: 0;
+ padding: 0 12px;
+ top: 0;
+ width: 100%;
+ height: 44px;
+ color: #23272f;
+ font-weight: 700;
+ font-size: 20px;
+ z-index: 100;
+ cursor: default;
+}
+
+.content {
+ padding: 0 12px;
+ margin-top: 4px;
+}
+
+
+.loader {
+ color: #23272f;
+ font-size: 3px;
+ width: 1em;
+ margin-right: 18px;
+ height: 1em;
+ border-radius: 50%;
+ position: relative;
+ text-indent: -9999em;
+ animation: loading-spinner 1.3s infinite linear;
+ animation-delay: 200ms;
+ transform: translateZ(0);
+}
+
+@keyframes loading-spinner {
+ 0%,
+ 100% {
+ box-shadow: 0 -3em 0 0.2em,
+ 2em -2em 0 0em, 3em 0 0 -1em,
+ 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 0;
+ }
+ 12.5% {
+ box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em,
+ 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 25% {
+ box-shadow: 0 -3em 0 -0.5em,
+ 2em -2em 0 0, 3em 0 0 0.2em,
+ 2em 2em 0 0, 0 3em 0 -1em,
+ -2em 2em 0 -1em, -3em 0 0 -1em,
+ -2em -2em 0 -1em;
+ }
+ 37.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em,
+ -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 50% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em,
+ -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em;
+ }
+ 62.5% {
+ box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0,
+ -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em;
+ }
+ 75% {
+ box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em,
+ 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0;
+ }
+ 87.5% {
+ box-shadow: 0em -3em 0 0, 2em -2em 0 -1em,
+ 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em,
+ -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em;
+ }
+}
+
+/* LikeButton */
+.like-button {
+ outline-offset: 2px;
+ position: relative;
+ display: flex;
+ align-items: center;
+ justify-content: center;
+ width: 2.5rem;
+ height: 2.5rem;
+ cursor: pointer;
+ border-radius: 9999px;
+ border: none;
+ outline: none 2px;
+ color: #5e687e;
+ background: none;
+}
+
+.like-button:focus {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+}
+
+.like-button:active {
+ color: #a6423a;
+ background-color: rgba(166, 66, 58, .05);
+ transform: scaleX(0.95) scaleY(0.95);
+}
+
+.like-button:hover {
+ background-color: #f6f7f9;
+}
+
+.like-button.liked {
+ color: #a6423a;
+}
+
+/* Icons */
+@keyframes circle {
+ 0% {
+ transform: scale(0);
+ stroke-width: 16px;
+ }
+
+ 50% {
+ transform: scale(.5);
+ stroke-width: 16px;
+ }
+
+ to {
+ transform: scale(1);
+ stroke-width: 0;
+ }
+}
+
+.circle {
+ color: rgba(166, 66, 58, .5);
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4,0,.2,1);
+}
+
+.circle.liked.animate {
+ animation: circle .3s forwards;
+}
+
+.heart {
+ width: 1.5rem;
+ height: 1.5rem;
+}
+
+.heart.liked {
+ transform-origin: center;
+ transition-property: all;
+ transition-duration: .15s;
+ transition-timing-function: cubic-bezier(.4, 0, .2, 1);
+}
+
+.heart.liked.animate {
+ animation: scale .35s ease-in-out forwards;
+}
+
+.control-icon {
+ color: hsla(0, 0%, 100%, .5);
+ filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08));
+}
+
+.chevron-left {
+ margin-top: 2px;
+ rotate: 90deg;
+}
+
+
+/* Video */
+.thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 8rem;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.thumbnail.blue {
+ background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491);
+}
+
+.thumbnail.red {
+ background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491);
+}
+
+.thumbnail.green {
+ background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491);
+}
+
+.thumbnail.purple {
+ background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491);
+}
+
+.thumbnail.yellow {
+ background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491);
+}
+
+.thumbnail.gray {
+ background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491);
+}
+
+.video {
+ display: flex;
+ flex-direction: row;
+ gap: 0.75rem;
+ align-items: center;
+}
+
+.video .link {
+ display: flex;
+ flex-direction: row;
+ flex: 1 1 0;
+ gap: 0.125rem;
+ outline-offset: 4px;
+ cursor: pointer;
+}
+
+.video .info {
+ display: flex;
+ flex-direction: column;
+ justify-content: center;
+ margin-left: 8px;
+ gap: 0.125rem;
+}
+
+.video .info:hover {
+ text-decoration: underline;
+}
+
+.video-title {
+ font-size: 15px;
+ line-height: 1.25;
+ font-weight: 700;
+ color: #23272f;
+}
+
+.video-description {
+ color: #5e687e;
+ font-size: 13px;
+}
+
+/* Details */
+.details .thumbnail {
+ position: relative;
+ aspect-ratio: 16 / 9;
+ display: flex;
+ overflow: hidden;
+ flex-direction: column;
+ justify-content: center;
+ align-items: center;
+ border-radius: 0.5rem;
+ outline-offset: 2px;
+ width: 100%;
+ vertical-align: middle;
+ background-color: #ffffff;
+ background-size: cover;
+ user-select: none;
+}
+
+.video-details-title {
+ margin-top: 8px;
+}
+
+.video-details-speaker {
+ display: flex;
+ gap: 8px;
+ margin-top: 10px
+}
+
+.back {
+ display: flex;
+ align-items: center;
+ margin-left: -5px;
+ cursor: pointer;
+}
+
+.back:hover {
+ text-decoration: underline;
+}
+
+.info-title {
+ font-size: 1.5rem;
+ font-weight: 700;
+ line-height: 1.25;
+ margin: 8px 0 0 0 ;
+}
+
+.info-description {
+ margin: 8px 0 0 0;
+}
+
+.controls {
+ cursor: pointer;
+}
+
+.fallback {
+ background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat;
+ background-size: 800px 104px;
+ display: block;
+ line-height: 1.25;
+ margin: 8px 0 0 0;
+ border-radius: 5px;
+ overflow: hidden;
+
+ animation: 1s linear 1s infinite shimmer;
+ animation-delay: 300ms;
+ animation-duration: 1s;
+ animation-fill-mode: forwards;
+ animation-iteration-count: infinite;
+ animation-name: shimmer;
+ animation-timing-function: linear;
+}
+
+
+.fallback.title {
+ width: 130px;
+ height: 30px;
+
+}
+
+.fallback.description {
+ width: 150px;
+ height: 21px;
+}
+
+@keyframes shimmer {
+ 0% {
+ background-position: -468px 0;
+ }
+
+ 100% {
+ background-position: 468px 0;
+ }
+}
+
+.search {
+ margin-bottom: 10px;
+}
+.search-input {
+ width: 100%;
+ position: relative;
+}
+
+.search-icon {
+ position: absolute;
+ top: 0;
+ bottom: 0;
+ inset-inline-start: 0;
+ display: flex;
+ align-items: center;
+ padding-inline-start: 1rem;
+ pointer-events: none;
+ color: #99a1b3;
+}
+
+.search-input input {
+ display: flex;
+ padding-inline-start: 2.75rem;
+ padding-top: 10px;
+ padding-bottom: 10px;
+ width: 100%;
+ text-align: start;
+ background-color: rgb(235 236 240);
+ outline: 2px solid transparent;
+ cursor: pointer;
+ border: none;
+ align-items: center;
+ color: rgb(35 39 47);
+ border-radius: 9999px;
+ vertical-align: middle;
+ font-size: 15px;
+}
+
+.search-input input:hover, .search-input input:active {
+ background-color: rgb(235 236 240/ 0.8);
+ color: rgb(35 39 47/ 0.8);
+}
+
+/* Home */
+.video-list {
+ position: relative;
+}
+
+.video-list .videos {
+ display: flex;
+ flex-direction: column;
+ gap: 1rem;
+ overflow-y: auto;
+ height: 100%;
+}
+```
+
+
+```css src/animations.css
+/* No additional animations needed */
+
+
+
+
+
+
+
+
+
+/* Previously defined animations below */
+
+
+
+
+
+::view-transition-old(.slow-fade) {
+ animation-duration: 500ms;
+}
+
+::view-transition-new(.slow-fade) {
+ animation-duration: 500ms;
+}
+```
+
+```js src/index.js hidden
+import React, {StrictMode} from 'react';
+import {createRoot} from 'react-dom/client';
+import './styles.css';
+import './animations.css';
+
+import App from './App';
+import {Router} from './router';
+
+const root = createRoot(document.getElementById('root'));
+root.render(
+
+
+
+
+);
+```
+
+```json package.json hidden
+{
+ "dependencies": {
+ "react": "experimental",
+ "react-dom": "experimental",
+ "react-scripts": "latest"
+ },
+ "scripts": {
+ "start": "react-scripts start",
+ "build": "react-scripts build",
+ "test": "react-scripts test --env=jsdom",
+ "eject": "react-scripts eject"
+ }
+}
+```
+
+
+
+By default, React automatically generates a unique `name` for each element activated for a transition (see [How does `
` work](/reference/react/ViewTransition#how-does-viewtransition-work)). When React sees a transition where a `` with a `name` is removed and a new `` with the same `name` is added, it will activate a shared element transition.
+
+For more info, see the docs for [Animating a Shared Element](/reference/react/ViewTransition#animating-a-shared-element).
+
+### Animating based on cause {/*animating-based-on-cause*/}
+
+Sometimes, you may want elements to animate differently based on how it was triggered. For this use case, we've added a new API called `addTransitionType` to specify the cause of a transition:
+
+```js {4,11}
+function navigate(url) {
+ startTransition(() => {
+ // Transition type for the cause "nav forward"
+ addTransitionType('nav-forward');
+ go(url);
+ });
+}
+function navigateBack(url) {
+ startTransition(() => {
+ // Transition type for the cause "nav backward"
+ addTransitionType('nav-back');
+ go(url);
+ });
+}
+```
+
+With transition types, you can provide custom animations via props to ``. Let's add a shared element transition to the header for "6 Videos" and "Back":
+
+```js {4,5}
+
+ {heading}
+
+```
+
+Here we pass a `share` prop to define how to animate based on the transition type. When the share transition activates from `nav-forward`, the view transition class `slide-forward` is applied. When it's from `nav-back`, the `slide-back` animation is activated. Let's define these animations in CSS:
+
+```css
+::view-transition-old(.slide-forward) {
+ /* when sliding forward, the "old" page should slide out to left. */
+ animation: ...
+}
+
+::view-transition-new(.slide-forward) {
+ /* when sliding forward, the "new" page should slide in from right. */
+ animation: ...
+}
+
+::view-transition-old(.slide-back) {
+ /* when sliding back, the "old" page should slide out to right. */
+ animation: ...
+}
+
+::view-transition-new(.slide-back) {
+ /* when sliding back, the "new" page should slide in from left. */
+ animation: ...
+}
+```
+
+Now we can animate the header along with thumbnail based on navigation type:
+
+
+
+```js src/App.js hidden
+import { unstable_ViewTransition as ViewTransition } from "react";
+import Details from "./Details";
+import Home from "./Home";
+import { useRouter } from "./router";
+
+export default function App() {
+ const { url } = useRouter();
+
+ // Keeping our default slow-fade.
+ return (
+
+ {url === "/" ?
+ );
+}
+```
+
+```js src/Details.js hidden
+import { fetchVideo, fetchVideoDetails } from "./data";
+import { Thumbnail, VideoControls } from "./Videos";
+import { useRouter } from "./router";
+import Layout from "./Layout";
+import { use, Suspense } from "react";
+import { ChevronLeft } from "./Icons";
+
+function VideoInfo({ id }) {
+ const details = use(fetchVideoDetails(id));
+ return (
+ <>
+ {details.title}
+ {details.description}
+
+ );
+}
+
+function VideoInfoFallback() {
+ return (
+ <>
+
+
+
+ );
+}
+
+export default function Details() {
+ const { url, navigateBack } = useRouter();
+ const videoId = url.split("/").pop();
+ const video = use(fetchVideo(videoId));
+
+ return (
+ {
+ navigateBack("/");
+ }}
+ >
+
+ }
+ >
+