0a527707cd
* Add Event Replaying Infra * Wire up Roots and Suspense boundaries, to retry events, after they commit * Replay discrete events in order in a separate scheduler callback * Add continuous events These events only replay their last target if the target is not yet hydrated. That way we don't have to wait for a previously hovered boundary before invoking the current target. * Enable tests from before These tests were written with replaying in mind and now we can properly enable them. * Unify replaying and dispatching * Mark system flags as a replay and pass to legacy events That way we can check if this is a replay and therefore needs a special case. One such special case is "mouseover" where we check the relatedTarget. * Eagerly listen to all replayable events To minimize breakages in a minor, I only do this for the new root APIs since replaying only matters there anyway. Only if hydrating. For Flare, I have to attach all active listeners since the current system has one DOM listener for each. In a follow up I plan on optimizing that by only attaching one if there's at least one active listener which would allow us to start with only passive and then upgrade. * Desperate attempt to save bytese * Add test for mouseover replaying We need to check if the "relatedTarget" is mounted due to how the old event system dispatches from the "out" event. * Fix for nested boundaries and suspense in root container This is a follow up to #16673 which didn't have a test because it wasn't observable yet. This shows that it had a bug. * Rename RESPONDER_EVENT_SYSTEM to PLUGIN_EVENT_SYSTEM
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.
Installation
React has been designed for gradual adoption from the start, and you can use as little or as much React as you need:
- Use Online Playgrounds to get a taste of React.
- Add React to a Website as a
<script>tag in one minute. - Create a New React App if you're looking for a powerful JavaScript toolchain.
You can use React as a <script> tag from a CDN, or as a react package on npm.
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:
function HelloMessage({ name }) {
return <div>Hello {name}</div>;
}
ReactDOM.render(
<HelloMessage name="Taylor" />,
document.getElementById('container')
);
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. If you're using React as a <script> tag, read this section on integrating JSX; otherwise, the recommended JavaScript toolchains handle it automatically.
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.