A declarative, efficient, and flexible JavaScript library for building user interfaces. reactjs.org
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Sebastian Markbåge 2e385738a4
Find Pairs and Apply View Transition Names to the Clones in the "old" Phase (#32599)
Stacked on #32578.

We need to apply view-transition-names to the clones that we create in
the "old" phase for the ViewTransition boundaries that should activate.

Finding pairs is a little trickier than in
ReactFiberCommitViewTransitions. Normally we collect all name
"insertions" in the `accumulateSuspenseyCommit` phase before we even
commit. Then in the snapshot do we visit all "deletions" and since we
already collected all the insertions we know immediately if the deletion
had a pair and should therefore get a "name" assigned to activate the
boundary. For ReactFiberApplyGesture we need to assign names to
"insertions" since it's in reverse but we don't already have a map of
deletions. Therefore we need to first visit all deletions.

Instead of doing that in a completely separate pass, we instead visit
deletions in the same pass to find pairs. Since this is in the same pass
we might visit insertions before deletions or vice versa depending on
document order. However, we can deal with this by applying the name to
the insertion when we find the deletion if we've already made the clones
at that point.

Applying names to pure exits, updates or nested (relayout) is a bit more
straight-forward.
2025-03-14 14:15:39 -04:00
.codesandbox Codesandbox: upgrade to Node.js 18 (#26330) 2023-03-06 15:38:03 -05:00
.github [ci] Update node_modules cache path (#32609) 2025-03-13 22:29:48 -04:00
compiler [compiler] detect and throw on untransformed required features (#32512) 2025-03-14 11:44:49 -04:00
fixtures feat(eslint-plugin-react-hooks): merge rule from eslint-plugin-react-compiler into react-hooks plugin (#32416) 2025-03-12 21:43:06 -04:00
packages Find Pairs and Apply View Transition Names to the Clones in the "old" Phase (#32599) 2025-03-14 14:15:39 -04:00
scripts [ci] Cache runtime and compiler only for test runs (#32608) 2025-03-13 22:21:35 -04:00
.editorconfig Remove trim_trailing_whitespace from editorconfig (#31413) 2024-11-04 15:30:02 -05:00
.eslintignore Fix ESLint and Prettier configs for React Compiler (#29073) 2024-05-15 14:02:57 -07:00
.eslintrc.js Rerender useSwipeTransition when direction changes (#32379) 2025-02-20 18:13:09 -05:00
.git-blame-ignore-revs Add run prettier commit to .git-blame-ignore-revs 2024-07-18 17:42:45 -04:00
.gitattributes .gitattributes to ensure LF line endings when we should 2014-01-17 16:25:53 -08:00
.gitignore [forgive] Init (#31918) 2025-02-25 12:19:11 -05:00
.mailmap updates mailmap entries (#19824) 2020-09-12 13:05:52 -04:00
.nvmrc [ci] Standardize node version and timezones 2024-07-12 12:53:05 -04:00
.prettierignore [prettier] Ignore compiler/target (#31168) 2024-10-10 10:53:27 -04:00
.prettierrc.js [BE] switch to hermes parser for prettier (#30421) 2024-07-22 19:16:13 -04:00
.watchmanconfig .watchmanconfig must be valid json (#16118) 2019-07-11 19:01:02 -07:00
babel.config-react-compiler.js feat(eslint-plugin-react-hooks): merge rule from eslint-plugin-react-compiler into react-hooks plugin (#32416) 2025-03-12 21:43:06 -04:00
babel.config-ts.js Update babel configs used in jest (#32588) 2025-03-12 19:07:39 -04:00
babel.config.js Update babel configs used in jest (#32588) 2025-03-12 19:07:39 -04:00
CHANGELOG-canary.md Add useActionState to CHANGELOG-canary.md (#28632) 2024-03-26 13:15:08 -04:00
CHANGELOG.md Fix headings in React 19 CHANGELOG (#31683) 2024-12-06 16:55:53 +01:00
CODE_OF_CONDUCT.md revert last grammatical edit (#25067) 2022-08-10 20:14:31 +01:00
CONTRIBUTING.md Fix: Updated link in CONTRIBUTING (#25381) 2022-10-03 10:29:57 -04:00
dangerfile.js Fix typo in dangerfile.js which results in an unreachable code path… (#32277) 2025-01-31 01:44:02 -05:00
LICENSE [Codemod] Update copyright header to Meta (#25315) 2022-10-18 11:19:24 -04:00
MAINTAINERS Update MAINTAINERS (#32238) 2025-01-27 13:40:45 -06:00
package.json [ci] Cache runtime and compiler only for test runs (#32608) 2025-03-13 22:21:35 -04:00
react.code-workspace created a vscode workspace file for the repo (#29830) 2024-06-13 16:23:42 +01:00
ReactVersions.js Fix canary version strings (#31721) 2024-12-12 14:11:24 -05:00
README.md [ez] Remove circleci badge from readme 2024-07-29 13:26:14 -04:00
SECURITY.md Create SECURITY.md (#15784) 2020-01-09 14:07:41 -08:00
yarn.lock feat(eslint-plugin-react-hooks): merge rule from eslint-plugin-react-compiler into react-hooks plugin (#32416) 2025-03-12 21:43:06 -04:00

React · GitHub license npm version (Runtime) Build and Test (Compiler) TypeScript PRs Welcome

React is a JavaScript library for building user interfaces.

  • Declarative: React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable, simpler to understand, and easier to debug.
  • Component-Based: Build encapsulated components that manage their own state, then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep the state out of the DOM.
  • Learn Once, Write Anywhere: We don't make assumptions about the rest of your technology stack, so you can develop new features in React without rewriting existing code. React can also render on the server using Node and power mobile apps using React Native.

Learn how to use React in your project.

Installation

React has been designed for gradual adoption from the start, and you can use as little or as much React as you need:

Documentation

You can find the React documentation on the website.

Check out the Getting Started page for a quick overview.

The documentation is divided into several sections:

You can improve it by sending pull requests to this repository.

Examples

We have several examples on the website. Here is the first one to get you started:

import { createRoot } from 'react-dom/client';

function HelloMessage({ name }) {
  return <div>Hello {name}</div>;
}

const root = createRoot(document.getElementById('container'));
root.render(<HelloMessage name="Taylor" />);

This example will render "Hello Taylor" into a container on the page.

You'll notice that we used an HTML-like syntax; we call it JSX. JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML.

Contributing

The main purpose of this repository is to continue evolving React core, making it faster and easier to use. Development of React happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React.

Code of Conduct

Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.

Contributing Guide

Read our contributing guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React.

Good First Issues

To help you get your feet wet and get you familiar with our contribution process, we have a list of good first issues that contain bugs that have a relatively limited scope. This is a great place to get started.

License

React is MIT licensed.