{tags.map((tag) => (
diff --git a/src/content/blog/2023/03/16/introducing-react-dev.md b/src/content/blog/2023/03/16/introducing-react-dev.md
index 2498f40d..c4da2b61 100644
--- a/src/content/blog/2023/03/16/introducing-react-dev.md
+++ b/src/content/blog/2023/03/16/introducing-react-dev.md
@@ -269,7 +269,7 @@ Use the conditional operator (`cond ? a : b`) to render a ❌ if `isPacked` isn
function Item({ name, isPacked }) {
return (
- {name} {isPacked && '✔'}
+ {name} {isPacked && '✅'}
);
}
@@ -307,7 +307,7 @@ export default function PackingList() {
function Item({ name, isPacked }) {
return (
- {name} {isPacked ? '✔' : '❌'}
+ {name} {isPacked ? '✅' : '❌'}
);
}
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 4d4355a4..f464df95 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
@@ -1,26 +1,18 @@
---
-title: "React 19 Beta Upgrade Guide"
+title: "React 19 RC Upgrade Guide"
author: Ricky Hanlon
date: 2024/04/25
-description: The improvements added to React 19 require some breaking changes, but we've worked to make the upgrade as smooth as possible and we don't expect the changes to impact most apps. In this post, we will guide you through the steps for upgrading libraries to React 19 beta.
+description: The improvements added to React 19 require some breaking changes, but we've worked to make the upgrade as smooth as possible and we don't expect the changes to impact most apps. In this post, we will guide you through the steps for upgrading apps and libraries to React 19.
---
April 25, 2024 by [Ricky Hanlon](https://twitter.com/rickhanlonii)
---
-
-
-This beta release is for libraries to prepare for React 19. App developers should upgrade to 18.3.0 and wait for React 19 stable as we work with libraries and make changes based on feedback.
-
-
-
-The improvements added to React 19 require some breaking changes, but we've worked to make the upgrade as smooth as possible and we don't expect the changes to impact most apps.
-
-To help make the upgrade easier, today we are also publishing React 18.3.
+The improvements added to React 19 RC require some breaking changes, but we've worked to make the upgrade as smooth as possible, and we don't expect the changes to impact most apps.
@@ -36,16 +28,17 @@ For a list of changes in 18.3 see the [Release Notes](https://github.com/faceboo
-In this post, we will guide you through the steps for upgrading libraries to React 19 beta:
+In this post, we will guide you through the steps for upgrading to React 19:
- [Installing](#installing)
+- [Codemods](#codemods)
- [Breaking changes](#breaking-changes)
- [New deprecations](#new-deprecations)
- [Notable changes](#notable-changes)
- [TypeScript changes](#typescript-changes)
- [Changelog](#changelog)
-If you'd like to help us test React 19, follow the steps in this upgrade guide and [report any issues](https://github.com/facebook/react/issues/new?assignees=&labels=React+19&projects=&template=19.md&title=%5BReact+19%5D) you encounter. For a list of new features added to React 19 beta, see the [React 19 release post](/blog/2024/04/25/react-19).
+If you'd like to help us test React 19, follow the steps in this upgrade guide and [report any issues](https://github.com/facebook/react/issues/new?assignees=&labels=React+19&projects=&template=19.md&title=%5BReact+19%5D) you encounter. For a list of new features added to React 19, see the [React 19 release post](/blog/2024/04/25/react-19).
---
## Installing {/*installing*/}
@@ -77,26 +70,63 @@ We expect most apps will not be affected since the transform is enabled in most
To install the latest version of React and React DOM:
```bash
-npm install react@beta react-dom@beta
+npm install --save-exact react@rc react-dom@rc
```
-If you're using TypeScript, you also need to update the types. Once React 19 is released as stable, you can install the types as usual from `@types/react` and `@types/react-dom`. During the beta period, the types are available in different packages which need to be enforced in your `package.json`:
+Or, if you're using Yarn:
+
+```bash
+yarn add --exact react@rc react-dom@rc
+```
+
+If you're using TypeScript, you also need to update the types. Once React 19 is released as stable, you can install the types as usual from `@types/react` and `@types/react-dom`. Until the stable release, the types are available in different packages which need to be enforced in your `package.json`:
```json
{
"dependencies": {
- "@types/react": "npm:types-react@beta",
- "@types/react-dom": "npm:types-react-dom@beta"
+ "@types/react": "npm:types-react@rc",
+ "@types/react-dom": "npm:types-react-dom@rc"
},
"overrides": {
- "@types/react": "npm:types-react@beta",
- "@types/react-dom": "npm:types-react-dom@beta"
+ "@types/react": "npm:types-react@rc",
+ "@types/react-dom": "npm:types-react-dom@rc"
}
}
```
We're also including a codemod for the most common replacements. See [TypeScript changes](#typescript-changes) below.
+## Codemods {/*codemods*/}
+
+To help with the upgrade, we've worked with the team at [codemod.com](https://codemod.com) to publish codemods that will automatically update your code to many of the new APIs and patterns in React 19.
+
+All codemods are available in the [`react-codemod` repo](https://github.com/reactjs/react-codemod) and the Codemod team have joined in helping maintain the codemods. To run these codemods, we recommend using the `codemod` command instead of the `react-codemod` because it runs faster, handles more complex code migrations, and provides better support for TypeScript.
+
+
+
+
+#### Run all React 19 codemods {/*run-all-react-19-codemods*/}
+
+Run all codemods listed in this guide with the React 19 `codemod` recipe:
+
+```bash
+npx codemod@latest react/19/migration-recipe
+```
+
+This will run the following codemods from `react-codemod`:
+- [`replace-reactdom-render`](https://github.com/reactjs/react-codemod?tab=readme-ov-file#replace-reactdom-render)
+- [`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`](TODO)
+
+This does not include the TypeScript changes. See [TypeScript changes](#typescript-changes) below.
+
+
+
+Changes that include a codemod include the command below.
+
+For a list of all available codemods, see the [`react-codemod` repo](https://github.com/reactjs/react-codemod).
## Breaking changes {/*breaking-changes*/}
@@ -128,7 +158,7 @@ For more info, see the docs for [`createRoot`](https://react.dev/reference/react
### Removed deprecated React APIs {/*removed-deprecated-react-apis*/}
#### Removed: `propTypes` and `defaultProps` for functions {/*removed-proptypes-and-defaultprops*/}
-`PropTypes` were deprecated in [April 2017 (v15.5.0)](https://legacy.reactjs.org/blog/2017/04/07/react-v15.5.0.html#new-deprecation-warnings).
+`PropTypes` were deprecated in [April 2017 (v15.5.0)](https://legacy.reactjs.org/blog/2017/04/07/react-v15.5.0.html#new-deprecation-warnings).
In React 19, we're removing the `propType` checks from the React package, and using them will be silently ignored. If you're using `propTypes`, we recommend migrating to TypeScript or another type-checking solution.
@@ -158,6 +188,16 @@ function Heading({text = 'Hello, world!'}: Props) {
}
```
+
+
+Codemod `propTypes` to TypeScript with:
+
+```bash
+npx codemod@latest react/prop-types-typescript
+```
+
+
+
#### Removed: Legacy Context using `contextTypes` and `getChildContext` {/*removed-removing-legacy-context*/}
Legacy Context was deprecated in [October 2018 (v16.6.0)](https://legacy.reactjs.org/blog/2018/10/23/react-v-16-6.html).
@@ -253,7 +293,11 @@ class MyComponent extends React.Component {
-To help with the migration, we will be publishing a [react-codemod](https://github.com/reactjs/react-codemod/#string-refs) to automatically replace string refs with `ref` callbacks. Follow [this PR](https://github.com/reactjs/react-codemod/pull/309) for updates and to try it out.
+Codemod string refs with `ref` callbacks:
+
+```bash
+npx codemod@latest react/19/replace-string-ref
+```
@@ -340,6 +384,16 @@ All other `test-utils` functions have been removed. These utilities were uncommo
See the [warning page](https://react.dev/warnings/react-dom-test-utils) for alternatives.
+
+
+Codemod `ReactDOMTestUtils.act` to `React.act`:
+
+```bash
+npx codemod@latest react/19/replace-act-import
+```
+
+
+
#### Removed: `ReactDOM.render` {/*removed-reactdom-render*/}
`ReactDOM.render` was deprecated in [March 2022 (v18.0.0)](https://react.dev/blog/2022/03/08/react-18-upgrade-guide). In React 19, we're removing `ReactDOM.render` and you'll need to migrate to using [`ReactDOM.createRoot`](https://react.dev/reference/react-dom/client/createRoot):
@@ -355,6 +409,16 @@ const root = createRoot(document.getElementById('root'));
root.render(
);
```
+
+
+Codemod `ReactDOM.render` to `ReactDOMClient.createRoot`:
+
+```bash
+npx codemod@latest react/19/replace-reactdom-render
+```
+
+
+
#### Removed: `ReactDOM.hydrate` {/*removed-reactdom-hydrate*/}
`ReactDOM.hydrate` was deprecated in [March 2022 (v18.0.0)](https://react.dev/blog/2022/03/08/react-18-upgrade-guide). In React 19, we're removing `ReactDOM.hydrate` you'll need to migrate to using [`ReactDOM.hydrateRoot`](https://react.dev/reference/react-dom/client/hydrateRoot),
@@ -369,6 +433,15 @@ import {hydrateRoot} from 'react-dom/client';
hydrateRoot(document.getElementById('root'),
);
```
+
+
+Codemod `ReactDOM.hydrate` to `ReactDOMClient.hydrateRoot`:
+
+```bash
+npx codemod@latest react/19/replace-reactdom-render
+```
+
+
#### Removed: `unmountComponentAtNode` {/*removed-unmountcomponentatnode*/}
@@ -385,8 +458,18 @@ root.unmount();
For more see `root.unmount()` for [`createRoot`](https://react.dev/reference/react-dom/client/createRoot#root-unmount) and [`hydrateRoot`](https://react.dev/reference/react-dom/client/hydrateRoot#root-unmount).
+
+
+Codemod `unmountComponentAtNode` to `root.unmount`:
+
+```bash
+npx codemod@latest react/19/replace-reactdom-render
+```
+
+
#### Removed: `ReactDOM.findDOMNode` {/*removed-reactdom-finddomnode*/}
+
`ReactDOM.findDOMNode` was [deprecated in October 2018 (v16.6.0)](https://legacy.reactjs.org/blog/2018/10/23/react-v-16-6.html#deprecations-in-strictmode).
We're removing `findDOMNode` because it was a legacy escape hatch that was slow to execute, fragile to refactoring, only returned the first child, and broke abstraction levels (see more [here](https://legacy.reactjs.org/docs/strict-mode.html#warning-about-deprecated-finddomnode-usage)). You can replace `ReactDOM.findDOMNode` with [DOM refs](/learn/manipulating-the-dom-with-refs):
diff --git a/src/content/blog/2024/04/25/react-19.md b/src/content/blog/2024/04/25/react-19.md
index 1ccffa1c..1b19c354 100644
--- a/src/content/blog/2024/04/25/react-19.md
+++ b/src/content/blog/2024/04/25/react-19.md
@@ -1,27 +1,21 @@
---
-title: "React 19 Beta"
+title: "React 19 RC"
author: The React Team
date: 2024/04/25
-description: React 19 Beta is now available on npm! In this post, we'll give an overview of the new features in React 19, and how you can adopt them.
+description: React 19 RC is now available on npm! In this post, we'll give an overview of the new features in React 19, and how you can adopt them.
---
April 25, 2024 by [The React Team](/community/team)
---
-
-
-This beta release is for libraries to prepare for React 19. App developers should upgrade to 18.3.0 and wait for React 19 stable as we work with libraries and make changes based on feedback.
-
-
-
-React 19 Beta is now available on npm!
+React 19 RC is now available on npm!
-In our [React 19 Beta Upgrade Guide](/blog/2024/04/25/react-19-upgrade-guide), we shared step-by-step instructions for upgrading your app to React 19 Beta. In this post, we'll give an overview of the new features in React 19, and how you can adopt them.
+In our [React 19 RC Upgrade Guide](/blog/2024/04/25/react-19-upgrade-guide), we shared step-by-step instructions for upgrading your app to React 19. In this post, we'll give an overview of the new features in React 19, and how you can adopt them.
- [What's new in React 19](#whats-new-in-react-19)
- [Improvements in React 19](#improvements-in-react-19)
@@ -510,8 +504,7 @@ Due to the introduction of ref cleanup functions, returning anything else from a
The original code returned the instance of the `HTMLDivElement` and TypeScript wouldn't know if this was _supposed_ to be a cleanup function or if you didn't want to return a cleanup function.
-You can codemod this pattern with [`no-implicit-ref-callback-return
-`](https://github.com/eps1lon/types-react-codemod/#no-implicit-ref-callback-return).
+You can codemod this pattern with [`no-implicit-ref-callback-return`](https://github.com/eps1lon/types-react-codemod/#no-implicit-ref-callback-return).
### `useDeferredValue` initial value {/*use-deferred-value-initial-value*/}
diff --git a/src/content/blog/2024/05/22/react-conf-2024-recap.md b/src/content/blog/2024/05/22/react-conf-2024-recap.md
new file mode 100644
index 00000000..96417fd8
--- /dev/null
+++ b/src/content/blog/2024/05/22/react-conf-2024-recap.md
@@ -0,0 +1,124 @@
+---
+title: "React Conf 2024 Recap"
+author: Ricky Hanlon
+date: 2024/05/22
+description: Last week we hosted React Conf 2024, a two-day conference in Henderson, Nevada where 700+ attendees gathered in-person to discuss the latest in UI engineering. In this post, we'll summarize the talks and announcements from the event.
+---
+
+May 22, 2024 by [Ricky Hanlon](https://twitter.com/rickhanlonii).
+
+---
+
+
+
+Last week we hosted React Conf 2024, a two-day conference in Henderson, Nevada where 700+ attendees gathered in-person to discuss the latest in UI engineering. This was our first in-person conference since 2019, and we were thrilled to be able to bring the community together again.
+
+
+
+---
+
+At React Conf 2024, we announced the [React 19 RC](/blog/2024/04/25/react-19), the [React Native New Architecture Beta](https://github.com/reactwg/react-native-new-architecture/discussions/189), and an experimental release of the [React Compiler](/learn/react-compiler). The community also took the stage to announce [React Router v7](https://remix.run/blog/merging-remix-and-react-router), [Universal Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=20765s) in Expo Router, React Server Components in [RedwoodJS](https://redwoodjs.com/blog/rsc-now-in-redwoodjs), and much more.
+
+The entire [day 1](https://www.youtube.com/watch?v=T8TZQ6k4SLE) and [day 2](https://www.youtube.com/watch?v=0ckOUBiuxVY) streams are available online. In this post, we'll summarize the talks and announcements from the event.
+
+## Day 1 {/*day-1*/}
+
+_[Watch the full day 1 stream here.](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=973s)_
+
+To kick off day 1, Meta CTO [Andrew "Boz" Bosworth](https://www.threads.net/@boztank) shared a welcome message followed by an introduction by [Seth Webster](https://twitter.com/sethwebster), who manages the React Org at Meta, and our MC [Ashley Narcisse](https://twitter.com/_darkfadr).
+
+In the day 1 keynote, [Joe Savona](https://twitter.com/en_JS) shared our goals and vision for React to make it easy for anyone to build great user experiences. [Lauren Tan](https://twitter.com/potetotes) followed with a State of React, where she shared that React was downloaded over 1 billion times in 2023, and that 37% of new developers learn to program with React. Finally, she highlighted the work of the React community to make React, React.
+
+For more, check out these talks from the community later in the conference:
+
+- [Vanilla React](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=5542s) by [Ryan Florence](https://twitter.com/ryanflorence)
+- [React Rhythm & Blues](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=12728s) by [Lee Robinson](https://twitter.com/leeerob)
+- [RedwoodJS, now with React Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=26815s) by [Amy Dutton](https://twitter.com/selfteachme)
+- [Introducing Universal React Server Components in Expo Router](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=20765s) by [Evan Bacon](https://twitter.com/Baconbrix)
+
+Next in the keynote, [Josh Story](https://twitter.com/joshcstory) and [Andrew Clark](https://twitter.com/acdlite) shared new features coming in React 19, and announced the React 19 RC which is ready for testing in production. Check out all the features in the [React 19 release post](/blog/2024/04/25/react-19), and see these talks for deep dives on the new features:
+
+- [What's new in React 19](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=8880s) by [Lydia Hallie](https://twitter.com/lydiahallie)
+- [React Unpacked: A Roadmap to React 19](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=10112s) by [Sam Selikoff](https://twitter.com/samselikoff)
+- [React 19 Deep Dive: Coordinating HTML](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=24916s) by [Josh Story](https://twitter.com/joshcstory)
+- [Enhancing Forms with React Server Components](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=25280s) by [Aurora Walberg Scharff](https://twitter.com/aurorascharff)
+- [React for Two Computers](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=18825s) by [Dan Abramov](https://twitter.com/dan_abramov2)
+- [And Now You Understand React Server Components](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=11256s) by [Kent C. Dodds](https://twitter.com/kentcdodds)
+
+Finally, we ended the keynote with [Joe Savona](https://twitter.com/en_JS), [Sathya Gunasekaran](https://twitter.com/_gsathya), and [Mofei Zhang](https://twitter.com/zmofei) announcing that the React Compiler is now [Open Source](https://github.com/facebook/react/pull/29061), and sharing an experimental version of the React Compiler to try out.
+
+For more information on using the Compiler and how it works, check out [the docs](/learn/react-compiler) and these talks:
+
+- [Forget About Memo](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=12020s) by [Lauren Tan](https://twitter.com/potetotes)
+- [React Compiler Deep Dive](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=9313s) by [Sathya Gunasekaran](https://twitter.com/_gsathya) and [Mofei Zhang](https://twitter.com/zmofei)
+
+Watch the full day 1 keynote here:
+
+
+
+## Day 2 {/*day-2*/}
+
+_[Watch the full day 2 stream here.](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=1720s)_
+
+To kick off day 2, [Seth Webster](https://twitter.com/sethwebster) shared a welcome message, followed by a Thank You from [Eli White](https://x.com/Eli_White) and an introduction by our Chief Vibes Officer [Ashley Narcisse](https://twitter.com/_darkfadr).
+
+In the day 2 keynote, [Nicola Corti](https://twitter.com/cortinico) shared the State of React Native, including 78 million downloads in 2023. He also highlighted apps using React Native including 2000+ screens used inside of Meta; the product details page in Facebook Marketplace, which is visited more than 2 billion times per day; and part of the Microsoft Windows Start Menu and some features in almost every Microsoft Office product across mobile and desktop.
+
+Nicola also highlighted all the work the community does to support React Native including libraries, frameworks, and multiple platforms. For more, check out these talks from the community:
+
+- [Extending React Native beyond Mobile and Desktop Apps](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=5798s) by [Chris Traganos](https://twitter.com/chris_trag) and [Anisha Malde](https://twitter.com/anisha_malde)
+- [Spatial computing with React](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=22525s) by [Michał Pierzchała](https://twitter.com/thymikee)
+
+[Riccardo Cipolleschi](https://twitter.com/cipolleschir) continued the day 2 keynote by announcing that the React Native New Architecture is now in Beta and ready for apps to adopt in production. He shared new features and improvements in the new architecture, and shared the roadmap for the future of React Native. For more check out:
+
+- [Cross Platform React](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=26569s) by [Olga Zinoveva](https://github.com/SlyCaptainFlint) and [Naman Goel](https://twitter.com/naman34)
+
+Next in the keynote, Nicola announced that we are now recommending starting with a framework like Expo for all new apps created with React Native. With the change, he also announced a new React Native homepage and new Getting Started docs. You can view the new Getting Started guide in the [React Native docs](https://reactnative.dev/docs/next/environment-setup).
+
+Finally, to end the keynote, [Kadi Kraman](https://twitter.com/kadikraman) shared the latest features and improvements in Expo, and how to get started developing with React Native using Expo.
+
+Watch the full day 2 keynote here:
+
+
+
+## Q&A {/*q-and-a*/}
+
+The React and React Native teams also ended each day with a Q&A session:
+
+- [React Q&A](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=27518s) hosted by [Michael Chan](https://twitter.com/chantastic)
+- [React Native Q&A](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=27935s) hosted by [Jamon Holmgren](https://twitter.com/jamonholmgren)
+
+## And more... {/*and-more*/}
+
+We also heard talks on accessibility, error reporting, css, and more:
+
+- [Demystifying accessibility in React apps](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=20655s) by [Kateryna Porshnieva](https://twitter.com/krambertech)
+- [Pigment CSS, CSS in the server component age](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=21696s) by [Olivier Tassinari](https://twitter.com/olivtassinari)
+- [Real-time React Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=24070s) by [Sunil Pai](https://twitter.com/threepointone)
+- [Let's break React Rules](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=25862s) by [Charlotte Isambert](https://twitter.com/c_isambert)
+- [Solve 100% of your errors](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=19881s) by [Ryan Albrecht](https://github.com/ryan953)
+
+## Thank you {/*thank-you*/}
+
+Thank you to all the staff, speakers, and participants who made React Conf 2024 possible. There are too many to list, but we want to thank a few in particular.
+
+Thank you to [Barbara Markiewicz](https://twitter.com/barbara_markie), the team at [Callstack](https://www.callstack.com/), and our React Team Developer Advocate [Matt Carroll](https://twitter.com/mattcarrollcode) for helping to plan the entire event; and to [Sunny Leggett](https://zeroslopeevents.com/about) and everyone from [Zero Slope](https://zeroslopeevents.com) for helping to organize the event.
+
+Thank you [Ashley Narcisse](https://twitter.com/_darkfadr) for being our MC and Chief Vibes Officer; and to [Michael Chan](https://twitter.com/chantastic) and [Jamon Holmgren](https://twitter.com/jamonholmgren) for hosting the Q&A sessions.
+
+Thank you [Seth Webster](https://twitter.com/sethwebster) and [Eli White](https://x.com/Eli_White) for welcoming us each day and providing direction on structure and content; and to [Tom Occhino](https://twitter.com/tomocchino) for joining us with a special message during the after-party.
+
+Thank you [Ricky Hanlon](https://www.youtube.com/watch?v=FxTZL2U-uKg&t=1263s) for providing detailed feedback on talks, working on slide designs, and generally filling in the gaps to sweat the details.
+
+Thank you [Callstack](https://www.callstack.com/) for building the conference website; and to [Kadi Kraman](https://twitter.com/kadikraman) and the [Expo](https://expo.dev/) team for building the conference mobile app.
+
+Thank you to all the sponsors who made the event possible: [Remix](https://remix.run/), [Amazon](https://developer.amazon.com/apps-and-games?cmp=US_2024_05_3P_React-Conf-2024&ch=prtnr&chlast=prtnr&pub=ref&publast=ref&type=org&typelast=org), [MUI](https://mui.com/), [Sentry](https://sentry.io/for/react/?utm_source=sponsored-conf&utm_medium=sponsored-event&utm_campaign=frontend-fy25q2-evergreen&utm_content=logo-reactconf2024-learnmore), [Abbott](https://www.jobs.abbott/software), [Expo](https://expo.dev/), [RedwoodJS](https://redwoodjs.com/), and [Vercel](https://vercel.com).
+
+Thank you to the AV Team for the visuals, stage, and sound; and to the Westin Hotel for hosting us.
+
+Thank you to all the speakers who shared their knowledge and experiences with the community.
+
+Finally, thank you to everyone who attended in person and online to show what makes React, React. React is more than a library, it is a community, and it was inspiring to see everyone come together to share and learn together.
+
+See you next time!
+
diff --git a/src/content/blog/index.md b/src/content/blog/index.md
index 24555902..4a1a165a 100644
--- a/src/content/blog/index.md
+++ b/src/content/blog/index.md
@@ -10,15 +10,21 @@ This blog is the official source for the updates from the React team. Anything i
-
+
-In the React 19 Beta Upgrade Guide, we shared step-by-step instructions for upgrading your app to React 19 Beta. In this post, we'll give an overview of the new features in React 19, and how you can adopt them.
+Last week we hosted React Conf 2024, a two-day conference in Henderson, Nevada where 700+ attendees gathered in-person to discuss the latest in UI engineering. This was our first in-person conference since 2019, and we were thrilled to be able to bring the community together again ...
-
+
-The improvements added to React 19 require some breaking changes, but we've worked to make the upgrade as smooth as possible and we don't expect the changes to impact most apps. In this post, we will guide you through the steps for upgrading libraries to React 19 beta.
+In the React 19 RC Upgrade Guide, we shared step-by-step instructions for upgrading your app to React 19. In this post, we'll give an overview of the new features in React 19, and how you can adopt them ...
+
+
+
+
+
+The improvements added to React 19 require some breaking changes, but we've worked to make the upgrade as smooth as possible, and we don't expect the changes to impact most apps. In this post, we will guide you through the steps for upgrading libraries to React 19 ...
diff --git a/src/content/community/conferences.md b/src/content/community/conferences.md
index dc0d60c5..cd0862b1 100644
--- a/src/content/community/conferences.md
+++ b/src/content/community/conferences.md
@@ -10,98 +10,122 @@ Do you know of a local React.js conference? Add it here! (Please keep the list c
## Upcoming Conferences {/*upcoming-conferences*/}
-### React Paris 2024 {/*react-paris-2024*/}
-March 22, 2024. In-person in Paris, France + Remote (hybrid)
+### React Universe Conf 2024 {/*react-universe-conf-2024*/}
+September 5-6, 2024. Wrocław, Poland.
-[Website](https://react.paris/) - [Twitter](https://twitter.com/BeJS_) - [LinkedIn](https://www.linkedin.com/events/7150816372074192900/comments/)
+[Website](https://www.reactuniverseconf.com/) - [Twitter](https://twitter.com/react_native_eu) - [LinkedIn](https://www.linkedin.com/events/reactuniverseconf7163919537074118657/)
-### Epic Web Conf 2024 {/*epic-web-2024*/}
-April 10 - 11, 2024. In-person in Park City, UT, USA
+### React Alicante 2024 {/*react-alicante-2024*/}
+September 19-21, 2024. Alicante, Spain.
-[Website](https://www.epicweb.dev/conf) - [YouTube](https://www.youtube.com/@EpicWebDev)
+[Website](https://reactalicante.es/) - [Twitter](https://twitter.com/ReactAlicante) - [YouTube](https://www.youtube.com/channel/UCaSdUaITU1Cz6PvC97A7e0w)
-### React Miami 2024 {/*react-miami-2024*/}
-April 19 - 20, 2024. In-person in Miami, FL, USA
+### RenderCon Kenya 2024 {/*rendercon-kenya-2024*/}
+October 04 - 05, 2024. Nairobi, Kenya
-[Website](https://reactmiami.com/) - [Twitter](https://twitter.com/ReactMiamiConf)
+[Website](https://rendercon.org/) - [Twitter](https://twitter.com/renderconke) - [LinkedIn](https://www.linkedin.com/company/renderconke/) - [YouTube](https://www.youtube.com/channel/UC0bCcG8gHUL4njDOpQGcMIA)
-### React Connection 2024 {/*react-connection-2024*/}
-April 22, 2024. In-person in Paris, France
+### React India 2024 {/*react-india-2024*/}
+October 17 - 19, 2024. In-person in Goa, India (hybrid event) + Oct 15 2024 - remote day
-[Website](https://reactconnection.io/) - [Twitter](https://twitter.com/ReactConn)
+[Website](https://www.reactindia.io) - [Twitter](https://twitter.com/react_india) - [Facebook](https://www.facebook.com/ReactJSIndia) - [Youtube](https://www.youtube.com/channel/UCaFbHCBkPvVv1bWs_jwYt3w)
-### React Native Connection 2024 {/*react-native-connection-2024*/}
-April 23, 2024. In-person in Paris, France
+### React Brussels 2024 {/*react-brussels-2024*/}
+October 18, 2024. In-person in Brussels, Belgium (hybrid event)
-[Website](https://reactnativeconnection.io/) - [Twitter](https://twitter.com/ReactNativeConn)
+[Website](https://www.react.brussels/) - [Twitter](https://x.com/BrusselsReact)
-### React Conf 2024 {/*react-conf-2024*/}
-May 15 - 16, 2024. In-person in Henderson, NV, USA + remote
+### React Advanced London 2024 {/*react-advanced-london-2024*/}
+October 25 & 28, 2024. In-person in London, UK + online (hybrid event)
-[Website](https://conf.react.dev) - [Twitter](https://twitter.com/reactjs)
+[Website](https://reactadvanced.com/) - [Twitter](https://x.com/reactadvanced)
-### App.js Conf 2024 {/*appjs-conf-2024*/}
-May 22 - 24, 2024. In-person in Kraków, Poland + remote
+### React Summit US 2024 {/*react-summit-us-2024*/}
+November 19 & 22, 2024. In-person in New York, USA + online (hybrid event)
-[Website](https://appjs.co) - [Twitter](https://twitter.com/appjsconf)
+[Website](https://reactsummit.us/) - [Twitter](https://twitter.com/reactsummit) - [Videos](https://portal.gitnation.org/)
-### Frontend Nation 2024 {/*frontend-nation-2024*/}
-June 4 - 7, 2024. Online
+### React Africa 2024 {/*react-africa-2024*/}
+November 29, 2024. In-person in Casablanca, Morocco (hybrid event)
-[Website](https://frontendnation.com/) - [Twitter](https://twitter.com/frontendnation)
+[Website](https://react-africa.com/) - [Twitter](https://x.com/BeJS_)
+
+### React Day Berlin 2024 {/*react-day-berlin-2024*/}
+December 13 & 16, 2024. In-person in Berlin, Germany + remote (hybrid event)
+
+[Website](https://reactday.berlin/) - [Twitter](https://x.com/reactdayberlin)
+
+## Past Conferences {/*past-conferences*/}
+
+### React Rally 2024 🐙 {/*react-rally-2024*/}
+August 12-13, 2024. Park City, UT, USA
+
+[Website](https://reactrally.com) - [Twitter](https://twitter.com/ReactRally) - [YouTube](https://www.youtube.com/channel/UCXBhQ05nu3L1abBUGeQ0ahw)
+
+### The Geek Conf 2024 {/*the-geek-conf-2024*/}
+July 25, 2024. In-person in Berlin, Germany + remote (hybrid event)
+
+[Website](https://thegeekconf.com) - [Twitter](https://twitter.com/thegeekconf)
+
+### Chain React 2024 {/*chain-react-2024*/}
+July 17-19, 2024. In-person in Portland, OR, USA
+
+[Website](https://chainreactconf.com) - [Twitter](https://twitter.com/ChainReactConf)
+
+### React Nexus 2024 {/*react-nexus-2024*/}
+July 04 & 05, 2024. Bangalore, India (In-person event)
+
+[Website](https://reactnexus.com/) - [Twitter](https://twitter.com/ReactNexus) - [Linkedin](https://www.linkedin.com/company/react-nexus) - [YouTube](https://www.youtube.com/reactify_in)
### React Summit 2024 {/*react-summit-2024*/}
June 14 & 18, 2024. In-person in Amsterdam, Netherlands + remote (hybrid event)
[Website](https://reactsummit.com/) - [Twitter](https://twitter.com/reactsummit) - [Videos](https://portal.gitnation.org/)
-### Render(ATL) 2024 🍑 {/*renderatl-2024-*/}
-June 12 - June 14, 2024. Atlanta, GA, USA
-
-[Website](https://renderatl.com) - [Discord](https://www.renderatl.com/discord) - [Twitter](https://twitter.com/renderATL) - [Instagram](https://www.instagram.com/renderatl/) - [Facebook](https://www.facebook.com/renderatl/) - [LinkedIn](https://www.linkedin.com/company/renderatl) - [Podcast](https://www.renderatl.com/culture-and-code#/)
-
### React Norway 2024 {/*react-norway-2024*/}
June 14, 2024. In-person at Farris Bad Hotel in Larvik, Norway and online (hybrid event).
[Website](https://reactnorway.com/) - [Twitter](https://twitter.com/ReactNorway)
-### React Nexus 2024 {/*react-nexus-2024*/}
-July 04 & 05, 2024. Bangalore, India (In-person event)
+### Render(ATL) 2024 🍑 {/*renderatl-2024-*/}
+June 12 - June 14, 2024. Atlanta, GA, USA
-[Website](https://reactnexus.com/) - [Twitter](https://twitter.com/ReactNexus) - [Linkedin](https://www.linkedin.com/company/react-nexus) - [YouTube](https://www.youtube.com/reactify_in)
+[Website](https://renderatl.com) - [Discord](https://www.renderatl.com/discord) - [Twitter](https://twitter.com/renderATL) - [Instagram](https://www.instagram.com/renderatl/) - [Facebook](https://www.facebook.com/renderatl/) - [LinkedIn](https://www.linkedin.com/company/renderatl) - [Podcast](https://www.renderatl.com/culture-and-code#/)
-### Chain React 2024 {/*chain-react-2024*/}
-July 17-19, 2024. In-person in Portland, OR, USA
+### Frontend Nation 2024 {/*frontend-nation-2024*/}
+June 4 - 7, 2024. Online
-[Website](https://chainreactconf.com) - [Twitter](https://twitter.com/ChainReactConf)
+[Website](https://frontendnation.com/) - [Twitter](https://twitter.com/frontendnation)
-### The Geek Conf 2024 {/*the-geek-conf-2024*/}
-July 25, 2024. In-person in Berlin, Germany + remote (hybrid event)
+### App.js Conf 2024 {/*appjs-conf-2024*/}
+May 22 - 24, 2024. In-person in Kraków, Poland + remote
-[Website](https://thegeekconf.com) - [Twitter](https://twitter.com/thegeekconf)
+[Website](https://appjs.co) - [Twitter](https://twitter.com/appjsconf)
-### React Rally 2024 🐙 {/*react-rally-2024*/}
-August 12-13, 2024. Park City, UT, USA
+### React Conf 2024 {/*react-conf-2024*/}
+May 15 - 16, 2024. In-person in Henderson, NV, USA + remote
-[Website](https://reactrally.com) - [Twitter](https://twitter.com/ReactRally) - [YouTube](https://www.youtube.com/channel/UCXBhQ05nu3L1abBUGeQ0ahw)
+[Website](https://conf.react.dev) - [Twitter](https://twitter.com/reactjs)
-### React Universe Conf 2024 {/*react-universe-conf-2024*/}
-September 5-6, 2024. Wrocław, Poland.
+### React Native Connection 2024 {/*react-native-connection-2024*/}
+April 23, 2024. In-person in Paris, France
-[Website](https://www.reactuniverseconf.com/) - [Twitter](https://twitter.com/react_native_eu) - [LinkedIn](https://www.linkedin.com/events/reactuniverseconf7163919537074118657/)
+[Website](https://reactnativeconnection.io/) - [Twitter](https://twitter.com/ReactNativeConn)
-### React Alicante 2024 {/*react-alicante-2024*/}
-September 19-21, 2024. Alicante, Spain.
+### React Miami 2024 {/*react-miami-2024*/}
+April 19 - 20, 2024. In-person in Miami, FL, USA
-[Website](https://reactalicante.es/) - [Twitter](https://twitter.com/ReactAlicante) - [YouTube](https://www.youtube.com/channel/UCaSdUaITU1Cz6PvC97A7e0w)
+[Website](https://reactmiami.com/) - [Twitter](https://twitter.com/ReactMiamiConf)
+### Epic Web Conf 2024 {/*epic-web-2024*/}
+April 10 - 11, 2024. In-person in Park City, UT, USA
-### React India 2024 {/*react-india-2024*/}
-October 17 - 19, 2024. In-person in Goa, India (hybrid event) + Oct 15 2024 - remote day
+[Website](https://www.epicweb.dev/conf) - [YouTube](https://www.youtube.com/@EpicWebDev)
-[Website](https://www.reactindia.io) - [Twitter](https://twitter.com/react_india) - [Facebook](https://www.facebook.com/ReactJSIndia) - [Youtube](https://www.youtube.com/channel/UCaFbHCBkPvVv1bWs_jwYt3w)
+### React Paris 2024 {/*react-paris-2024*/}
+March 22, 2024. In-person in Paris, France + Remote (hybrid)
-## Past Conferences {/*past-conferences*/}
+[Website](https://react.paris/) - [Twitter](https://twitter.com/BeJS_) - [LinkedIn](https://www.linkedin.com/events/7150816372074192900/comments/) - [Videos](https://www.youtube.com/playlist?list=PL53Z0yyYnpWhUzgvr2Nys3kZBBLcY0TA7)
### React Day Berlin 2023 {/*react-day-berlin-2023*/}
December 8 & 12, 2023. In-person in Berlin, Germany + remote first interactivity (hybrid event)
diff --git a/src/content/community/meetups.md b/src/content/community/meetups.md
index a12a5349..d8887c3d 100644
--- a/src/content/community/meetups.md
+++ b/src/content/community/meetups.md
@@ -100,7 +100,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
* [Ahmedabad](https://www.meetup.com/react-ahmedabad/)
* [Bangalore (React)](https://www.meetup.com/ReactJS-Bangalore/)
* [Bangalore (React Native)](https://www.meetup.com/React-Native-Bangalore-Meetup)
-* [Chennai](https://www.meetup.com/React-Chennai/)
+* [Chennai](https://www.linkedin.com/company/chennaireact)
* [Delhi NCR](https://www.meetup.com/React-Delhi-NCR/)
* [Mumbai](https://reactmumbai.dev)
* [Pune](https://www.meetup.com/ReactJS-and-Friends/)
diff --git a/src/content/learn/adding-interactivity.md b/src/content/learn/adding-interactivity.md
index 0d4a3b23..5c87a3e7 100644
--- a/src/content/learn/adding-interactivity.md
+++ b/src/content/learn/adding-interactivity.md
@@ -265,7 +265,7 @@ setCount(count + 1); // Request a re-render with 1
console.log(count); // Still 0!
```
-This behavior help you avoid subtle bugs. Here is a little chat app. Try to guess what happens if you press "Send" first and *then* change the recipient to Bob. Whose name will appear in the `alert` five seconds later?
+This behavior helps you avoid subtle bugs. Here is a little chat app. Try to guess what happens if you press "Send" first and *then* change the recipient to Bob. Whose name will appear in the `alert` five seconds later?
diff --git a/src/content/learn/conditional-rendering.md b/src/content/learn/conditional-rendering.md
index 895d610d..95be5d2e 100644
--- a/src/content/learn/conditional-rendering.md
+++ b/src/content/learn/conditional-rendering.md
@@ -52,13 +52,13 @@ export default function PackingList() {
-Notice that some of the `Item` components have their `isPacked` prop set to `true` instead of `false`. You want to add a checkmark (✔) to packed items if `isPacked={true}`.
+Notice that some of the `Item` components have their `isPacked` prop set to `true` instead of `false`. You want to add a checkmark (✅) to packed items if `isPacked={true}`.
You can write this as an [`if`/`else` statement](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else) like so:
```js
if (isPacked) {
- return {name} ✔;
+ return {name} ✅;
}
return {name};
```
@@ -70,7 +70,7 @@ If the `isPacked` prop is `true`, this code **returns a different JSX tree.** Wi
```js
function Item({ name, isPacked }) {
if (isPacked) {
- return {name} ✔;
+ return {name} ✅;
}
return {name};
}
@@ -159,7 +159,7 @@ In practice, returning `null` from a component isn't common because it might sur
In the previous example, you controlled which (if any!) JSX tree would be returned by the component. You may already have noticed some duplication in the render output:
```js
-{name} ✔
+{name} ✅
```
is very similar to
@@ -172,7 +172,7 @@ Both of the conditional branches return `...`:
```js
if (isPacked) {
- return {name} ✔;
+ return {name} ✅;
}
return {name};
```
@@ -187,7 +187,7 @@ Instead of this:
```js
if (isPacked) {
- return {name} ✔;
+ return {name} ✅;
}
return {name};
```
@@ -197,12 +197,12 @@ You can write this:
```js
return (
- {isPacked ? name + ' ✔' : name}
+ {isPacked ? name + ' ✅' : name}
);
```
-You can read it as *"if `isPacked` is true, then (`?`) render `name + ' ✔'`, otherwise (`:`) render `name`"*.
+You can read it as *"if `isPacked` is true, then (`?`) render `name + ' ✅'`, otherwise (`:`) render `name`"*.
@@ -222,7 +222,7 @@ function Item({ name, isPacked }) {
{isPacked ? (
- {name + ' ✔'}
+ {name + ' ✅'}
) : (
name
@@ -265,7 +265,7 @@ Another common shortcut you'll encounter is the [JavaScript logical AND (`&&`) o
```js
return (
- {name} {isPacked && '✔'}
+ {name} {isPacked && '✅'}
);
```
@@ -280,7 +280,7 @@ Here it is in action:
function Item({ name, isPacked }) {
return (
- {name} {isPacked && '✔'}
+ {name} {isPacked && '✅'}
);
}
@@ -337,7 +337,7 @@ Use an `if` statement to reassign a JSX expression to `itemContent` if `isPacked
```js
if (isPacked) {
- itemContent = name + " ✔";
+ itemContent = name + " ✅";
}
```
@@ -357,7 +357,7 @@ This style is the most verbose, but it's also the most flexible. Here it is in a
function Item({ name, isPacked }) {
let itemContent = name;
if (isPacked) {
- itemContent = name + " ✔";
+ itemContent = name + " ✅";
}
return (
@@ -401,7 +401,7 @@ function Item({ name, isPacked }) {
if (isPacked) {
itemContent = (
- {name + " ✔"}
+ {name + " ✅"}
);
}
@@ -464,7 +464,7 @@ Use the conditional operator (`cond ? a : b`) to render a ❌ if `isPacked` isn
function Item({ name, isPacked }) {
return (
- {name} {isPacked && '✔'}
+ {name} {isPacked && '✅'}
);
}
@@ -502,7 +502,7 @@ export default function PackingList() {
function Item({ name, isPacked }) {
return (
- {name} {isPacked ? '✔' : '❌'}
+ {name} {isPacked ? '✅' : '❌'}
);
}
diff --git a/src/content/learn/describing-the-ui.md b/src/content/learn/describing-the-ui.md
index ce49b85c..34ee0c01 100644
--- a/src/content/learn/describing-the-ui.md
+++ b/src/content/learn/describing-the-ui.md
@@ -327,7 +327,7 @@ In this example, the JavaScript `&&` operator is used to conditionally render a
function Item({ name, isPacked }) {
return (
- {name} {isPacked && '✔'}
+ {name} {isPacked && '✅'}
);
}
diff --git a/src/content/learn/installation.md b/src/content/learn/installation.md
index c5426ea9..7251fc31 100644
--- a/src/content/learn/installation.md
+++ b/src/content/learn/installation.md
@@ -37,7 +37,7 @@ export default function App() {
You can edit it directly or open it in a new tab by pressing the "Fork" button in the upper right corner.
-Most pages in the React documentation contain sandboxes like this. Outside of the React documentation, there are many online sandboxes that support React: for example, [CodeSandbox](https://codesandbox.io/s/new), [StackBlitz](https://stackblitz.com/fork/react), or [CodePen.](https://codepen.io/pen?&editors=0010&layout=left&prefill_data_id=3f4569d1-1b11-4bce-bd46-89090eed5ddb)
+Most pages in the React documentation contain sandboxes like this. Outside of the React documentation, there are many online sandboxes that support React: for example, [CodeSandbox](https://codesandbox.io/s/new), [StackBlitz](https://stackblitz.com/fork/react), or [CodePen.](https://codepen.io/pen?template=QWYVwWN)
### Try React locally {/*try-react-locally*/}
diff --git a/src/content/learn/react-compiler.md b/src/content/learn/react-compiler.md
index 23c7f86a..2920e864 100644
--- a/src/content/learn/react-compiler.md
+++ b/src/content/learn/react-compiler.md
@@ -21,7 +21,7 @@ These docs are still a work in progress. More documentation is available in the
React Compiler is a new experimental compiler that we've open sourced to get early feedback from the community. It still has rough edges and is not yet fully ready for production.
-React Compiler requires React 19 Beta.
+React Compiler requires React 19 RC. If you are unable to upgrade to React 19, you may try a userspace implementation of the cache function as described in the [Working Group](https://github.com/reactwg/react-compiler/discussions/6). However, please note that this is not recommended and you should upgrade to React 19 when possible.
React Compiler is a new experimental compiler that we've open sourced to get early feedback from the community. It is a build-time only tool that automatically optimizes your React app. It works with plain JavaScript, and understands the [Rules of React](/reference/rules), so you don't need to rewrite any code to use it.
@@ -30,72 +30,105 @@ The compiler also includes an [eslint plugin](#installing-eslint-plugin-react-co
### What does the compiler do? {/*what-does-the-compiler-do*/}
-The compiler understands your code at a deep level through its understanding of plain JavaScript semantics and the [Rules of React](/reference/rules). This allows it to add automatic optimizations to your code.
+In order to optimize applications, React Compiler automatically memoizes your code. You may be familiar today with memoization through APIs such as `useMemo`, `useCallback`, and `React.memo`. With these APIs you can tell React that certain parts of your application don't need to recompute if their inputs haven't changed, reducing work on updates. While powerful, it's easy to forget to apply memoization or apply them incorrectly. This can lead to inefficient updates as React has to check parts of your UI that don't have any _meaningful_ changes.
-You may be familiar today with manual memoization through [`useMemo`](/reference/react/useMemo), [`useCallback`](/reference/react/useCallback), and [`React.memo`](/reference/react/memo). The compiler can automatically do this for you, if your code follows the [Rules of React](/reference/rules). If it detects breakages of the rules, it will automatically skip over just those components or hooks, and continue safely compiling other code.
+The compiler uses its knowledge of JavaScript and React's rules to automatically memoize values or groups of values within your components and hooks. If it detects breakages of the rules, it will automatically skip over just those components or hooks, and continue safely compiling other code.
-If your codebase is already very well memoized, you might not expect to see major performance improvements with the compiler. However, in practice memoizing the correct dependencies that cause performance issues is tricky to get right by hand.
+If your codebase is already very well-memoized, you might not expect to see major performance improvements with the compiler. However, in practice memoizing the correct dependencies that cause performance issues is tricky to get right by hand.
-### Should I try out the compiler? {/*should-i-try-out-the-compiler*/}
+
+#### What kind of memoization does React Compiler add? {/*what-kind-of-memoization-does-react-compiler-add*/}
-Please note that the compiler is still experimental and has many rough edges. While it has been used in production at companies like Meta, rolling out the compiler to production for your app will depend on the health of your codebase and how well you've followed the [Rules of React](/reference/rules).
+The initial release of React Compiler is primarily focused on **improving update performance** (re-rendering existing components), so it focuses on these two use cases:
-**You don't have to rush into using the compiler now. It's okay to wait until it reaches a stable release before adopting it.** However, we do appreciate trying it out in small experiments in your apps so that you can [provide feedback](#reporting-issues) to us to help make the compiler better.
+1. **Skipping cascading re-rendering of components**
+ * Re-rendering `` causes many components in its component tree to re-render, even though only `` has changed
+1. **Skipping expensive calculations from outside of React**
+ * For example, calling `expensivelyProcessAReallyLargeArrayOfObjects()` inside of your component or hook that needs that data
-## Getting Started {/*getting-started*/}
+#### Optimizing Re-renders {/*optimizing-re-renders*/}
-In addition to these docs, we recommend checking the [React Compiler Working Group](https://github.com/reactwg/react-compiler) for additional information and discussion about the compiler.
+React lets you express your UI as a function of their current state (more concretely: their props, state, and context). In its current implementation, when a component's state changes, React will re-render that component _and all of its children_ — unless you have applied some form of manual memoization with `useMemo()`, `useCallback()`, or `React.memo()`. For example, in the following example, `` will re-render whenever ``'s state changes:
-### Rolling out the compiler to your codebase {/*using-the-compiler-effectively*/}
+```javascript
+function FriendList({ friends }) {
+ const onlineCount = useFriendOnlineCount();
+ if (friends.length === 0) {
+ return ;
+ }
+ return (
+
+ {onlineCount} online
+ {friends.map((friend) => (
+
+ ))}
+
+
+ );
+}
+```
+[_See this example in the React Compiler Playground_](https://playground.react.dev/#N4Igzg9grgTgxgUxALhAMygOzgFwJYSYAEAYjHgpgCYAyeYOAFMEWuZVWEQL4CURwADrEicQgyKEANnkwIAwtEw4iAXiJQwCMhWoB5TDLmKsTXgG5hRInjRFGbXZwB0UygHMcACzWr1ABn4hEWsYBBxYYgAeADkIHQ4uAHoAPksRbisiMIiYYkYs6yiqPAA3FMLrIiiwAAcAQ0wU4GlZBSUcbklDNqikusaKkKrgR0TnAFt62sYHdmp+VRT7SqrqhOo6Bnl6mCoiAGsEAE9VUfmqZzwqLrHqM7ubolTVol5eTOGigFkEMDB6u4EAAhKA4HCEZ5DNZ9ErlLIWYTcEDcIA)
-#### Existing projects {/*existing-projects*/}
-The compiler is designed to compile functional components and hooks that follow the [Rules of React](/reference/rules). It can also handle code that breaks those rules by bailing out (skipping over) those components or hooks. However, due to the flexible nature of JavaScript, the compiler cannot catch every possible violation and may compile with false negatives: that is, the compiler may accidentally compile a component/hook that breaks the Rules of React which can lead to undefined behavior.
+React Compiler automatically applies the equivalent of manual memoization, ensuring that only the relevant parts of an app re-render as state changes, which is sometimes referred to as "fine-grained reactivity". In the above example, React Compiler determines that the return value of `` can be reused even as `friends` changes, and can avoid recreating this JSX _and_ avoid re-rendering `` as the count changes.
-For this reason, to adopt the compiler successfully on existing projects, we recommend running it on a small directory in your product code first. You can do this by configuring the compiler to only run on a specific set of directories:
+#### Expensive calculations also get memoized {/*expensive-calculations-also-get-memoized*/}
-```js {3}
-const ReactCompilerConfig = {
- sources: (filename) => {
- return filename.indexOf('src/path/to/dir') !== -1;
- },
-};
-```
-
-In rare cases, you can also configure the compiler to run in "opt-in" mode using the `compilationMode: "annotation"` option. This makes it so the compiler will only compile components and hooks annotated with a `"use memo"` directive. Please note that the `annotation` mode is a temporary one to aid early adopters, and that we don't intend for the `"use memo"` directive to be used for the long term.
+The compiler can also automatically memoize for expensive calculations used during rendering:
-```js {2,7}
-const ReactCompilerConfig = {
- compilationMode: "annotation",
-};
+```js
+// **Not** memoized by React Compiler, since this is not a component or hook
+function expensivelyProcessAReallyLargeArrayOfObjects() { /* ... */ }
-// src/app.jsx
-export default function App() {
- "use memo";
+// Memoized by React Compiler since this is a component
+function TableContainer({ items }) {
+ // This function call would be memoized:
+ const data = expensivelyProcessAReallyLargeArrayOfObjects(items);
// ...
}
```
+[_See this example in the React Compiler Playground_](https://playground.react.dev/#N4Igzg9grgTgxgUxALhAejQAgFTYHIQAuumAtgqRAJYBeCAJpgEYCemASggIZyGYDCEUgAcqAGwQwANJjBUAdokyEAFlTCZ1meUUxdMcIcIjyE8vhBiYVECAGsAOvIBmURYSonMCAB7CzcgBuCGIsAAowEIhgYACCnFxioQAyXDAA5gixMDBcLADyzvlMAFYIvGAAFACUmMCYaNiYAHStOFgAvk5OGJgAshTUdIysHNy8AkbikrIKSqpaWvqGIiZmhE6u7p7ymAAqXEwSguZcCpKV9VSEFBodtcBOmAYmYHz0XIT6ALzefgFUYKhCJRBAxeLcJIsVIZLI5PKFYplCqVa63aoAbm6u0wMAQhFguwAPPRAQA+YAfL4dIloUmBMlODogDpAA)
-When you have more confidence with rolling out the compiler, you can expand coverage to other directories as well and slowly roll it out to your whole app.
+However, if `expensivelyProcessAReallyLargeArrayOfObjects` is truly an expensive function, you may want to consider implementing its own memoization outside of React, because:
-#### New projects {/*new-projects*/}
+- React Compiler only memoizes React components and hooks, not every function
+- React Compiler's memoization is not shared across multiple components or hooks
-If you're starting a new project, you can enable the compiler on your entire codebase, which is the default behavior.
+So if `expensivelyProcessAReallyLargeArrayOfObjects` was used in many different components, even if the same exact items were passed down, that expensive calculation would be run repeatedly. We recommend [profiling](https://react.dev/reference/react/useMemo#how-to-tell-if-a-calculation-is-expensive) first to see if it really is that expensive before making code more complicated.
+
+
+### What does the compiler assume? {/*what-does-the-compiler-assume*/}
+
+React Compiler assumes that your code:
-## Installation {/*installation*/}
+1. Is valid, semantic JavaScript
+2. Tests that nullable/optional values and properties are defined before accessing them (for example, by enabling [`strictNullChecks`](https://www.typescriptlang.org/tsconfig/#strictNullChecks) if using TypeScript), i.e., `if (object.nullableProperty) { object.nullableProperty.foo }` or with optional-chaining `object.nullableProperty?.foo`
+3. Follows the [Rules of React](https://react.dev/reference/rules)
+
+React Compiler can verify many of the Rules of React statically, and will safely skip compilation when it detects an error. To see the errors we recommend also installing [eslint-plugin-react-compiler](https://www.npmjs.com/package/eslint-plugin-react-compiler).
+
+### Should I try out the compiler? {/*should-i-try-out-the-compiler*/}
+
+Please note that the compiler is still experimental and has many rough edges. While it has been used in production at companies like Meta, rolling out the compiler to production for your app will depend on the health of your codebase and how well you've followed the [Rules of React](/reference/rules).
+
+**You don't have to rush into using the compiler now. It's okay to wait until it reaches a stable release before adopting it.** However, we do appreciate trying it out in small experiments in your apps so that you can [provide feedback](#reporting-issues) to us to help make the compiler better.
+
+## Getting Started {/*getting-started*/}
+
+In addition to these docs, we recommend checking the [React Compiler Working Group](https://github.com/reactwg/react-compiler) for additional information and discussion about the compiler.
### Checking compatibility {/*checking-compatibility*/}
Prior to installing the compiler, you can first check to see if your codebase is compatible:
-npx react-compiler-healthcheck
+npx react-compiler-healthcheck@experimental
This script will:
- Check how many components can be successfully optimized: higher is better
- Check for `` usage: having this enabled and followed means a higher chance that the [Rules of React](/reference/rules) are followed
-- Check for incompatible library usage: known libaries that are incompatible with the compiler
+- Check for incompatible library usage: known libraries that are incompatible with the compiler
As an example:
@@ -110,7 +143,7 @@ Found no usage of incompatible libraries.
React Compiler also powers an eslint plugin. The eslint plugin can be used **independently** of the compiler, meaning you can use the eslint plugin even if you don't use the compiler.
-npm install eslint-plugin-react-compiler
+npm install eslint-plugin-react-compiler@experimental
Then, add it to your eslint config:
@@ -126,10 +159,51 @@ module.exports = {
}
```
-### Usage with Babel {/*usage-with-babel*/}
+The eslint plugin will display any violations of the rules of React in your editor. When it does this, it means that the compiler has skipped over optimizing that component or hook. This is perfectly okay, and the compiler can recover and continue optimizing other components in your codebase.
+
+**You don't have to fix all eslint violations straight away.** You can address them at your own pace to increase the amount of components and hooks being optimized, but it is not required to fix everything before you can use the compiler.
+
+### Rolling out the compiler to your codebase {/*using-the-compiler-effectively*/}
+
+#### Existing projects {/*existing-projects*/}
+The compiler is designed to compile functional components and hooks that follow the [Rules of React](/reference/rules). It can also handle code that breaks those rules by bailing out (skipping over) those components or hooks. However, due to the flexible nature of JavaScript, the compiler cannot catch every possible violation and may compile with false negatives: that is, the compiler may accidentally compile a component/hook that breaks the Rules of React which can lead to undefined behavior.
+
+For this reason, to adopt the compiler successfully on existing projects, we recommend running it on a small directory in your product code first. You can do this by configuring the compiler to only run on a specific set of directories:
+
+```js {3}
+const ReactCompilerConfig = {
+ sources: (filename) => {
+ return filename.indexOf('src/path/to/dir') !== -1;
+ },
+};
+```
+
+In rare cases, you can also configure the compiler to run in "opt-in" mode using the `compilationMode: "annotation"` option. This makes it so the compiler will only compile components and hooks annotated with a `"use memo"` directive. Please note that the `annotation` mode is a temporary one to aid early adopters, and that we don't intend for the `"use memo"` directive to be used for the long term.
+
+```js {2,7}
+const ReactCompilerConfig = {
+ compilationMode: "annotation",
+};
+
+// src/app.jsx
+export default function App() {
+ "use memo";
+ // ...
+}
+```
+
+When you have more confidence with rolling out the compiler, you can expand coverage to other directories as well and slowly roll it out to your whole app.
+
+#### New projects {/*new-projects*/}
+
+If you're starting a new project, you can enable the compiler on your entire codebase, which is the default behavior.
+
+## Usage {/*installation*/}
+
+### Babel {/*usage-with-babel*/}
-npm install babel-plugin-react-compiler
+npm install babel-plugin-react-compiler@experimental
The compiler includes a Babel plugin which you can use in your build pipeline to run the compiler.
@@ -152,7 +226,7 @@ module.exports = function () {
`babel-plugin-react-compiler` should run first before other Babel plugins as the compiler requires the input source information for sound analysis.
-### Usage with Vite {/*usage-with-vite*/}
+### Vite {/*usage-with-vite*/}
If you use Vite, you can add the plugin to vite-plugin-react:
@@ -176,7 +250,7 @@ export default defineConfig(() => {
});
```
-### Usage with Next.js {/*usage-with-nextjs*/}
+### Next.js {/*usage-with-nextjs*/}
Next.js has an experimental configuration to enable the React Compiler. It automatically ensures Babel is set up with `babel-plugin-react-compiler`.
@@ -184,7 +258,7 @@ Next.js has an experimental configuration to enable the React Compiler. It autom
- Install `babel-plugin-react-compiler`
-npm install next@canary babel-plugin-react-compiler
+npm install next@canary babel-plugin-react-compiler@experimental
Then configure the experimental option in `next.config.js`:
@@ -209,7 +283,7 @@ Using the experimental option ensures support for the React Compiler in:
- Turbopack (opt-in through `--turbo`)
-### Usage with Remix {/*usage-with-remix*/}
+### Remix {/*usage-with-remix*/}
Install `vite-plugin-babel`, and add the compiler's Babel plugin to it:
@@ -238,7 +312,7 @@ export default defineConfig({
});
```
-### Usage with Webpack {/*usage-with-webpack*/}
+### Webpack {/*usage-with-webpack*/}
You can create your own loader for React Compiler, like so:
@@ -267,7 +341,7 @@ function reactCompilerLoader(sourceCode, sourceMap) {
this.callback(
null,
- result.code
+ result.code,
result.map === null ? undefined : result.map
);
}
@@ -275,37 +349,62 @@ function reactCompilerLoader(sourceCode, sourceMap) {
module.exports = reactCompilerLoader;
```
-### Usage with Expo {/*usage-with-expo*/}
+### Expo {/*usage-with-expo*/}
-Expo uses Babel via Metro, so refer to the [Usage with Babel](#usage-with-babel) section for installation instructions.
+Please refer to [Expo's docs](https://docs.expo.dev/preview/react-compiler/) to enable and use the React Compiler in Expo apps.
-### Usage with React Native (Metro) {/*usage-with-react-native-metro*/}
+### Metro (React Native) {/*usage-with-react-native-metro*/}
React Native uses Babel via Metro, so refer to the [Usage with Babel](#usage-with-babel) section for installation instructions.
-## Troubleshooting {/*troubleshooting*/}
+### Rspack {/*usage-with-rspack*/}
-### Reporting Issues {/*reporting-issues*/}
+Please refer to [Rspack's docs](https://rspack.dev/guide/tech/react#react-compiler) to enable and use the React Compiler in Rspack apps.
-To report issues, please first create a minimal repro on the [React Compiler Playground](https://playground.react.dev/) and include it in your bug report.
+### Rsbuild {/*usage-with-rsbuild*/}
+
+Please refer to [Rsbuild's docs](https://rsbuild.dev/guide/framework/react#react-compiler) to enable and use the React Compiler in Rsbuild apps.
+
+## Troubleshooting {/*troubleshooting*/}
-You can open issues in the [facebook/react](https://github.com/facebook/react/issues) repo.
+To report issues, please first create a minimal repro on the [React Compiler Playground](https://playground.react.dev/) and include it in your bug report. You can open issues in the [facebook/react](https://github.com/facebook/react/issues) repo.
You can also provide feedback in the React Compiler Working Group by applying to be a member. Please see [the README for more details on joining](https://github.com/reactwg/react-compiler).
-### Common Issues {/*common-issues*/}
+### `(0 , _c) is not a function` error {/*0--_c-is-not-a-function-error*/}
-#### `(0 , _c) is not a function` error {/*0--_c-is-not-a-function-error*/}
+This occurs if you are not using React 19 RC and up. To fix this, [upgrade your app to React 19 RC](https://react.dev/blog/2024/04/25/react-19-upgrade-guide) first.
-This occurs during JavaScript module evaluation when you are not using React 19 Beta and up. To fix this, [upgrade your app to React 19 Beta](https://react.dev/blog/2024/04/25/react-19-upgrade-guide) first.
+If you are unable to upgrade to React 19, you may try a userspace implementation of the cache function as described in the [Working Group](https://github.com/reactwg/react-compiler/discussions/6). However, please note that this is not recommended and you should upgrade to React 19 when possible.
-### Debugging {/*debugging*/}
+### How do I know my components have been optimized? {/*how-do-i-know-my-components-have-been-optimized*/}
-#### Checking if components have been optimized {/*checking-if-components-have-been-optimized*/}
-##### React DevTools {/*react-devtools*/}
+[React Devtools](/learn/react-developer-tools) (v5.0+) has built-in support for React Compiler and will display a "Memo ✨" badge next to components that have been optimized by the compiler.
+
+### Something is not working after compilation {/*something-is-not-working-after-compilation*/}
+If you have eslint-plugin-react-compiler installed, the compiler will display any violations of the rules of React in your editor. When it does this, it means that the compiler has skipped over optimizing that component or hook. This is perfectly okay, and the compiler can recover and continue optimizing other components in your codebase. **You don't have to fix all eslint violations straight away.** You can address them at your own pace to increase the amount of components and hooks being optimized.
+
+Due to the flexible and dynamic nature of JavaScript however, it's not possible to comprehensively detect all cases. Bugs and undefined behavior such as infinite loops may occur in those cases.
+
+If your app doesn't work properly after compilation and you aren't seeing any eslint errors, the compiler may be incorrectly compiling your code. To confirm this, try to make the issue go away by aggressively opting out any component or hook you think might be related via the [`"use no memo"` directive](#opt-out-of-the-compiler-for-a-component).
+
+```js {2}
+function SuspiciousComponent() {
+ "use no memo"; // opts out this component from being compiled by React Compiler
+ // ...
+}
+```
+
+
+#### `"use no memo"` {/*use-no-memo*/}
+
+`"use no memo"` is a _temporary_ escape hatch that lets you opt-out components and hooks from being compiled by the React Compiler. This directive is not meant to be long lived the same way as eg [`"use client"`](/reference/rsc/use-client) is.
+
+It is not recommended to reach for this directive unless it's strictly necessary. Once you opt-out a component or hook, it is opted-out forever until the directive is removed. This means that even if you fix the code, the compiler will still skip over compiling it unless you remove the directive.
+
-React Devtools (v5.0+) has built-in support for React Compiler and will display a "Memo ✨" badge next to components that have been optimized by the compiler.
+When you make the error go away, confirm that removing the opt out directive makes the issue come back. Then share a bug report with us (you can try to reduce it to a small repro, or if it's open source code you can also just paste the entire source) using the [React Compiler Playground](https://playground.react.dev) so we can identify and help fix the issue.
-##### Other issues {/*other-issues*/}
+### Other issues {/*other-issues*/}
Please see https://github.com/reactwg/react-compiler/discussions/7.
diff --git a/src/content/learn/reusing-logic-with-custom-hooks.md b/src/content/learn/reusing-logic-with-custom-hooks.md
index 13a556c7..67de5e97 100644
--- a/src/content/learn/reusing-logic-with-custom-hooks.md
+++ b/src/content/learn/reusing-logic-with-custom-hooks.md
@@ -1899,7 +1899,7 @@ export default function Counter() {
}
```
-You'll need to write your custom Hook in `useCounter.js` and import it into the `Counter.js` file.
+You'll need to write your custom Hook in `useCounter.js` and import it into the `App.js` file.
diff --git a/src/content/learn/synchronizing-with-effects.md b/src/content/learn/synchronizing-with-effects.md
index 9ca10965..48e99cc2 100644
--- a/src/content/learn/synchronizing-with-effects.md
+++ b/src/content/learn/synchronizing-with-effects.md
@@ -1600,7 +1600,7 @@ Each render's Effect has its own `ignore` variable. Initially, the `ignore` vari
- Fetching `'Bob'` completes
- The Effect from the `'Bob'` render **does not do anything because its `ignore` flag was set to `true`**
-In addition to ignoring the result of an outdated API call, you can also use [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController) to cancel the requests that are no longer needed. However, by itself this is not enough to protect against race conditions. More asynchronous steps could be chained after the fetch, so using an explicit flag like `ignore` is the most reliable way to fix this type of problems.
+In addition to ignoring the result of an outdated API call, you can also use [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController) to cancel the requests that are no longer needed. However, by itself this is not enough to protect against race conditions. More asynchronous steps could be chained after the fetch, so using an explicit flag like `ignore` is the most reliable way to fix this type of problem.
diff --git a/src/content/learn/you-might-not-need-an-effect.md b/src/content/learn/you-might-not-need-an-effect.md
index 66cdc311..a009793a 100644
--- a/src/content/learn/you-might-not-need-an-effect.md
+++ b/src/content/learn/you-might-not-need-an-effect.md
@@ -408,9 +408,9 @@ function Game() {
There are two problems with this code.
-One problem is that it is very inefficient: the component (and its children) have to re-render between each `set` call in the chain. In the example above, in the worst case (`setCard` → render → `setGoldCardCount` → render → `setRound` → render → `setIsGameOver` → render) there are three unnecessary re-renders of the tree below.
+The first problem is that it is very inefficient: the component (and its children) have to re-render between each `set` call in the chain. In the example above, in the worst case (`setCard` → render → `setGoldCardCount` → render → `setRound` → render → `setIsGameOver` → render) there are three unnecessary re-renders of the tree below.
-Even if it weren't slow, as your code evolves, you will run into cases where the "chain" you wrote doesn't fit the new requirements. Imagine you are adding a way to step through the history of the game moves. You'd do it by updating each state variable to a value from the past. However, setting the `card` state to a value from the past would trigger the Effect chain again and change the data you're showing. Such code is often rigid and fragile.
+The second problem is that even if it weren't slow, as your code evolves, you will run into cases where the "chain" you wrote doesn't fit the new requirements. Imagine you are adding a way to step through the history of the game moves. You'd do it by updating each state variable to a value from the past. However, setting the `card` state to a value from the past would trigger the Effect chain again and change the data you're showing. Such code is often rigid and fragile.
In this case, it's better to calculate what you can during rendering, and adjust the state in the event handler:
diff --git a/src/content/reference/react-dom/components/index.md b/src/content/reference/react-dom/components/index.md
index c9b355c8..ec2e1d2e 100644
--- a/src/content/reference/react-dom/components/index.md
+++ b/src/content/reference/react-dom/components/index.md
@@ -34,7 +34,7 @@ They are special in React because passing the `value` prop to them makes them *[
## Resource and Metadata Components {/*resource-and-metadata-components*/}
-These bulit-in browser components let you load external resources or annotate the document with metadata:
+These built-in browser components let you load external resources or annotate the document with metadata:
* [``](/reference/react-dom/components/link)
* [``](/reference/react-dom/components/meta)
diff --git a/src/content/reference/react-dom/components/link.md b/src/content/reference/react-dom/components/link.md
index 9172a66e..730d9e99 100644
--- a/src/content/reference/react-dom/components/link.md
+++ b/src/content/reference/react-dom/components/link.md
@@ -43,7 +43,7 @@ To link to external resources such as stylesheets, fonts, and icons, or to annot
These props apply when `rel="stylesheet"`:
-* `precedence`: a string. Tells React where to rank the `` DOM node relative to others in the document ``, which determines which stylesheet can override the other. Its value can be (in order of precedence) `"reset"`, `"low"`, `"medium"`, `"high"`. Stylesheets with the same precedence go together whether they are `` or inline `