Andrew ClarkandGitHub
862f499fac
* Add Batched Mode React has an unfortunate quirk where updates are sometimes synchronous -- where React starts rendering immediately within the call stack of `setState` — and sometimes batched, where updates are flushed at the end of the current event. Any update that originates within the call stack of the React event system is batched. This encompasses most updates, since most updates originate from an event handler like `onClick` or `onChange`. It also includes updates triggered by lifecycle methods or effects. But there are also updates that originate outside React's event system, like timer events, network events, and microtasks (promise resolution handlers). These are not batched, which results in both worse performance (multiple render passes instead of single one) and confusing semantics. Ideally all updates would be batched by default. Unfortunately, it's easy for components to accidentally rely on this behavior, so changing it could break existing apps in subtle ways. One way to move to a batched-by-default model is to opt into Concurrent Mode (still experimental). But Concurrent Mode introduces additional semantic changes that apps may not be ready to adopt. This commit introduces an additional mode called Batched Mode. Batched Mode enables a batched-by-default model that defers all updates to the next React event. Once it begins rendering, React will not yield to the browser until the entire render is finished. Batched Mode is superset of Strict Mode. It fires all the same warnings. It also drops the forked Suspense behavior used by Legacy Mode, in favor of the proper semantics used by Concurrent Mode. I have not added any public APIs that expose the new mode yet. I'll do that in subsequent commits. * Suspense in Batched Mode Should have same semantics as Concurrent Mode. * Use RootTag field to configure type of root There are three types of roots: Legacy, Batched, and Concurrent. * flushSync should not flush batched work Treat Sync and Batched expiration times separately. Only Sync updates are pushed to our internal queue of synchronous callbacks. Renamed `flushImmediateQueue` to `flushSyncCallbackQueue` for clarity.
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.