A declarative, efficient, and flexible JavaScript library for building user interfaces. reactjs.org
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Eugene Choi d4374b3ae3
[compiler] [playground] Show internals toggle (#34399)
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## Summary

Added a "Show Internals" toggle switch to either show only the Config,
Input, Output, and Source Map tabs, or these tabs + all the additional
compiler options. The open/close state of these tabs will be preserved
(unless on page refresh, which is the same as the currently
functionality).


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Explain the **motivation** for making this change. What existing problem
does the pull request solve?
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https://github.com/user-attachments/assets/8eb0f69e-360c-4e9b-9155-7aa185a0c018
2025-09-08 14:21:03 -04:00
.codesandbox Update Code Sandbox CI to Node 20 to Match .nvmrc (#34329) 2025-08-28 18:33:12 -04:00
.github [ci] Cache playwright in run_devtools_e2e_tests (#34320) 2025-08-27 14:37:18 -04:00
compiler [compiler] [playground] Show internals toggle (#34399) 2025-09-08 14:21:03 -04:00
fixtures [Flight] Use more robust web socket implementation in fixture (#34338) 2025-08-29 12:04:27 +02:00
flow-typed Update Flow to 0.265 (#34270) 2025-08-22 15:22:22 -04:00
packages [Flight] Always initialize a debug info array for each Chunk (#34419) 2025-09-08 12:28:14 -04:00
scripts Add scrollIntoView to fragment instances (#32814) 2025-08-27 18:05:57 -04:00
.editorconfig Remove trim_trailing_whitespace from editorconfig (#31413) 2024-11-04 15:30:02 -05:00
.eslintignore Update Flow to 0.263 (#34269) 2025-08-22 12:10:13 -04:00
.eslintrc.js [DevTools] Allow inspection before streaming has finished in Chrome (#34360) 2025-09-04 12:21:06 +02:00
.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 Upgrade node.js to 20 LTS (#32855) 2025-04-14 12:52:02 -04:00
.prettierignore [prettier] Ignore compiler/target (#31168) 2024-10-10 10:53:27 -04:00
.prettierrc.js [scripts] Switch back to flow parser for prettier (#33414) 2025-06-03 00:00:28 -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 [compiler] Aggregate error reporting, separate eslint rules (#34176) 2025-08-21 14:53:34 -07:00
babel.config.js Partially revert #32588 (#32621) 2025-03-15 15:21:57 -04:00
CHANGELOG.md Clean up 19.1.1 changelog (#34023) 2025-07-28 17:32:23 +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
flow-typed.config.json Update Flow to 0.263 (#34269) 2025-08-22 12:10:13 -04:00
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 Update Flow to 0.279 (#34277) 2025-08-25 11:02:56 -04:00
react.code-workspace created a vscode workspace file for the repo (#29830) 2024-06-13 16:23:42 +01:00
ReactVersions.js [eprh] Bump stable version (#32978) 2025-04-21 14:36:13 -04:00
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 Update Flow to 0.279 (#34277) 2025-08-25 11:02:56 -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.