* Extract Jest config into a separate file
* Refactor Jest scripts directory structure
Introduces a more consistent naming scheme.
* Add yarn test-bundles and yarn test-prod-bundles
Only files ending with -test.public.js are opted in (so far we don't have any).
* Fix error decoding for production bundles
GCC seems to remove `new` from `new Error()` which broke our proxy.
* Build production version of react-noop-renderer
This lets us test more bundles.
* Switch to blacklist (exclude .private.js tests)
* Rename tests that are currently broken against bundles to *-test.internal.js
Some of these are using private APIs. Some have other issues.
* Add bundle tests to CI
* Split private and public ReactJSXElementValidator tests
* Remove internal deps from ReactServerRendering-test and make it public
* Only run tests directly in __tests__
This lets us share code between test files by placing them in __tests__/utils.
* Remove ExecutionEnvironment dependency from DOMServerIntegrationTest
It's not necessary since Stack.
* Split up ReactDOMServerIntegration into test suite and utilities
This enables us to further split it down. Good both for parallelization and extracting public parts.
* Split Fragment tests from other DOMServerIntegration tests
This enables them to opt other DOMServerIntegration tests into bundle testing.
* Split ReactDOMServerIntegration into different test files
It was way too slow to run all these in sequence.
* Don't reset the cache twice in DOMServerIntegration tests
We used to do this to simulate testing separate bundles.
But now we actually *do* test bundles. So there is no need for this, as it makes tests slower.
* Rename test-bundles* commands to test-build*
Also add test-prod-build as alias for test-build-prod because I keep messing them up.
* Use regenerator polyfill for react-noop
This fixes other issues and finally lets us run ReactNoop tests against a prod bundle.
* Run most Incremental tests against bundles
Now that GCC generator issue is fixed, we can do this.
I split ErrorLogging test separately because it does mocking. Other error handling tests don't need it.
* Update sizes
* Fix ReactMount test
* Enable ReactDOMComponent test
* Fix a warning issue uncovered by flat bundle testing
With flat bundles, we couldn't produce a good warning for <div onclick={}> on SSR
because it doesn't use the event system. However the issue was not visible in normal
Jest runs because the event plugins have been injected by the time the test ran.
To solve this, I am explicitly passing whether event system is available as an argument
to the hook. This makes the behavior consistent between source and bundle tests. Then
I change the tests to document the actual logic and _attempt_ to show a nice message
(e.g. we know for sure `onclick` is a bad event but we don't know the right name for it
on the server so we just say a generic message about camelCase naming convention).
React ·

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 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 own project.
Documentation
You can find the React documentation on the website.
It 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:
class HelloMessage extends React.Component {
render() {
return <div>Hello {this.props.name}</div>;
}
}
ReactDOM.render(
<HelloMessage name="John" />,
document.getElementById('container')
);
This example will render "Hello John" 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. We recommend using Babel with a React preset to convert JSX into native JavaScript for browsers to digest.
Installation
React is available as the react package on npm. It is also available on a CDN.
React is flexible and can be used in a variety of projects. You can create new apps with it, but you can also gradually introduce it into an existing codebase without doing a rewrite.
The recommended way to install React depends on your project. Here you can find short guides for the most common scenarios:
Contributing
The main purpose of this repository is to continue to evolve 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 which have a relatively limited scope. This is a great place to get started.
License
React is MIT licensed.